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At least 19 recordsLinked to original sources

PubMed1993

SURVIVAL--an integrated software package for survival curve estimation and statistical comparison of survival rates of two groups of patients or experimental animals.

SURVIVAL, a new integrated software package for survival curve estimation and statistical comparison of survival rates of two censored or uncensored groups of patients or experimental animals, is described and demonstrated. The software is based on the calculation of the Kaplan-Meier estimates of survival curves and utilizes the Mantel-Haenszel and/or Fisher's test for the statistical comparison of the corresponding survival rates. SURVIVAL can be used for statistical evaluation of survival data obtained either on sequentially created or fixed size groups. The software is menu driven to provide a very user friendly tool for analyzing survival data. It may be of great value mainly in clinical use because it automatically enables evaluation of a large set of survival data, sequentially collected in SURVIVAL's own database during a long survival study, with entry and evaluation possible at any time during the study.

Animals↗

PubMed2004

Micrometastasis of a sentinel lymph node in cutaneous melanoma is a significant prognostic factor for disease-free survival, distant-metastasis-free survival, and overall survival.

OBJECTIVE: Sentinel lymph node biopsy (SLNB) has been proposed as a minimally invasive procedure for the histopathologic staging of the regional lymph node basin. The aim of this work was to investigate the prognostic value of detection of micrometastasis by SLNB. METHODS: In the period from January 1996 to March 2000, a sentinel lymph node (SLN) was identified in 283 patients at the Department Dermatology, University of Tuebingen. In the case of 38 patients (13.4%) histopathologic examination led to the detection of micrometastasis in at least one SLN. The median follow-up period was 29 months. RESULTS: Thirty-one of 245 patients (12.7%) suffered a tumor recurrence following a negative SLNB, and 19 of 38 patients (50%) following positive SLNB. In the case of disease-free survival the remaining significant independent prognostic factors of the multivariate analysis were tumor thickness (p=0.011), ulceration (p=0.026), and the detection of micrometastasis in SLNB (p=0.021). With respect to distant-metastasis-free survival the significant independent prognostic factors of the multivariate analysis were tumor thickness (p=0.0022) and the SLNB results (p=0.0068). For overall survival the tumor thickness (p=0.013) and the SLNB results (p=0.034) were significant independent prognostic parameters in the multivariate analysis. CONCLUSION: The study examined patients with melanomas of all tumor thicknesses and SLNB for which the prognostic significance of SLNB was tested. Recurrences were more frequent in patients with a micrometastatic SLN. Patients with a negative SNLB are still at risk for tumor recurrence. The histopathologic result of SLNB is, after tumor thickness, the most significant prognostic factor for disease-free survival, distant-metastasis-free survival, and overall survival.

Disease-Free Survival↗

PubMed2005

Preoperative radiation with concurrent chemotherapy for resectable rectal cancer: effect of dose escalation on pathologic complete response, local recurrence-free survival, disease-free survival, and overall survival.

PURPOSE: Three Phase II studies of preoperative radiotherapy and concurrent 5FU chemotherapy were undertaken. The primary endpoints were acute toxicity and pathologic complete response rate (pCR). Secondary endpoints were local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS). METHODS AND MATERIALS: A total of 134 patients with adenocarcinoma of the rectum (clinical T3/T4 or N1/N2) were treated. The initial cohort received 40 Gy in 20 fractions, the second 46 Gy in 23 fractions, and the third 50 Gy in 25 fractions. 5FU (225 mg/m2/day) was given continuously throughout radiotherapy. A total of 121 patients underwent surgical resection. RESULTS: Treatment was well tolerated. Grade 3/4 acute toxicity was observed in 13%, 4%, and 14% of patients in the 40 Gy, 46 Gy, and 50 Gy cohorts, respectively (p = 0.20). pCR was documented in 15%, 23%, and 33% of patients, respectively (p = 0.07). The 2-year actuarial LRFS was 72%, 90%, and 89% (p = 0.02); DFS was 62%, 84%, and 78% (p = 0.02); and OS was 72%, 94%, and 92%, respectively (p = 0.03). CONCLUSIONS: All treatment schedules were well tolerated. There was a trend toward increased pCR with higher doses. A statistically significant increase in LRFS, DFS, and OS was seen with radiation doses of 46 Gy and greater, but there was no difference between 46 Gy and 50 Gy.

Antimetabolites, Antineoplastic↗

PubMed2003

Independently derived survival risk ratios yield better estimates of survival than traditional survival risk ratios when using the ICISS.

BACKGROUND: The International Classification of Diseases, Ninth Revision Injury Severity Score (ICISS) is criticized because it relies on survival risk ratios (SRRs) that are contaminated by incidents with multiple injuries. An SRR for an International Classification of Diseases, Ninth Revision code is the number of patients who survive the injury divided by the number who display it. The ICISS is the product of SRRs that correspond to a patient's injuries. Traditional SRRs are derived from databases that include patients with multiple injuries and are biased toward mortality, making them nonindependent. Independent SRRs are derived from incidents where patients sustained only an isolated injury. The objective of this study is to compare the mortality prediction abilities of independent and traditional SRRs via the ICISS. METHODS: A 10-fold cross-validation design was used to estimate independent and traditional SRRs and their resulting ICISSs from 192,347 National Trauma Data Bank patients. Logistic regression modeled the scores as a function of mortality. The area under the receiver operating characteristic curve measured discrimination. Model fit was measured with the Akaike information criterion, a deviance statistic (lower is better). R2 values were compared to determine which score explained the most variance. RESULTS: The independent ICISS statistically outperforms the traditional ICISS. CONCLUSION: Traditional SRRs used by the ICISS produce less accurate estimates of mortality than independent SRRs. The ICISS can be calculated in 97.9% of incidents using independent SRRs.

Databases as Topic↗

PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗

PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗

PubMed1989

Cause-specific actuarial survival analysis: a useful method for reporting survival data in men with clinically localized carcinoma of the prostate.

The primary objective of this retrospective 15-year survival analysis of 57 men with clinical stage B1 carcinoma of the prostate undergoing radical prostatectomy between 1951 and 1963 is to compute the cause-specific curve for these men and argue why it is a useful method to report survival data in men with clinically localized prostatic cancer. Historically, survival following radical prostatectomy and radiotherapy has been reported using all cause survival analysis. Cause-specific survival focuses on the impact of a disease process on survival, since men dying of causes unrelated to carcinoma of the prostate are considered lost to followup as of date of death of such unrelated causes. Cause-specific survival analysis reduces the impact of age, medical condition and other risk factors on survival rates. The cause-specific 15-year actuarial survival rate in our patients was 86 per cent. The 95 per cent confidence interval for this 15-year survival rate was 76.9 to 90.1 per cent. Based upon this series of patients with clinical stage B1 carcinoma of the prostate who undergo radical prostatectomy one may state that the chance of death of carcinoma of the prostate within 15 years of surgery averages 14 +/- 5 per cent. The cause-specific survival curve reached a plateau at 10 years, indicating that most men who survive 10 years are cured of the disease. With the Cox model regression analysis, mortality in this series was related positively to age at operation when the outcome variable was death of all causes (p equals 0.003) but it was unrelated to age when the outcome variable was prostate cancer mortality (p equals 0.85). Cause-specific survival rates are a more precise indicator of the impact of a therapeutic modality on survival and, therefore, they are useful to report survival data in men with localized carcinoma of the prostate and other disease when death from competing causes is an important consideration.

Actuarial Analysis↗

PubMed2003

First-year survival of infants born with congenital heart defects in Arkansas (1993-1998): a survival analysis using registry data.

BACKGROUND: In the United States and other developed nations, birth defects are the leading cause of infant mortality. Congenital heart defects (CHDs) are among the most prevalent and fatal of all birth defects. Here we report the survival probability of infants born with CHDs in Arkansas and examine the impact of multiple malformations on survival. METHODS: Birth and death certificate records were linked to birth defects registry data for infants born with CHDs from January 1993 through December 1998 in Arkansas. Both neonatal and first-year survival probabilities were estimated. These were computed non-parametrically using Kaplan-Meier's product limit method. A Cox proportional-hazards model was used to evaluate the relative importance of additional malformations on survival. RESULTS: A total of 1,983 infants with CHDs were included in this study. The neonatal survival probability for this cohort was 94.0% (95% CI: 93.0%, 95.1%), and the first-year survival probability was 88.2% (95% CI: 86.8%, 89.6%). The presence of hypoplastic left heart syndrome conferred the greatest reduction in survival, whereas infants with pulmonic valve stenosis and infants with ventricular septal defects had the highest first-year survival. Infants with multiple CHDs had decreased survival compared to those with isolated heart defects. Survival was also adversely affected by the presence of congenital abnormalities in other body systems. CONCLUSIONS: Neonatal and first-year survival of infants with CHDs varies by both the type of cardiac malformation and the presence of additional cardiac and non-cardiac malformations. Further work will focus on the effects of maternal and infant characteristics on survival.

Abnormalities, Multiple↗

PubMed1998

Survival, disease-free survival and adverse effects of conditioning for allogeneic bone marrow transplantation with busulfan/cyclophosphamide vs total body irradiation: a meta-analysis.

Randomized, prospective studies comparing BUCY to TBI conditioning regimens for allogeneic bone marrow transplantation have yielded conflicting results. We investigated the overall survival, the disease-free survival and the toxicities of BUCY vs TBI-based regimens by conducting a meta-analysis of all published, randomized, prospective trials comparing these regimens. Five studies were analyzed. We evaluated six endpoints: survival, disease-free survival, veno-occlusive disease (VOD) of the liver, acute GVHD, chronic GVHD, and interstitial pneumonitis. We combined individual study results using a random effects model. Survival and disease-free survival were better with TBI-based regimens than with BUCY, but these differences were not statistically significant (survival odds ratio 1.4, 95% confidence interval 0.9-2.2, P = 0.09; disease-free survival odds ratio 1.2, 95% confidence interval 0.7-2.1, P = 0.44). A power analysis indicated that BUCY was unlikely to have a clinically relevant survival or disease-free survival advantage. The power analysis could not exclude the possibility of such an advantage for TBI-based regimens. A significantly greater incidence of VOD occurred with BUCY (odds ratio 2.5, 95% confidence interval 1.2-5.2, P = 0.02). For the other side-effects, there were no significant differences. We concluded that TBI-based regimens cause less VOD than BUCY and are at least as good for survival and disease-free survival.

Adult↗

PubMed1994

Survival estimates for 683 patients starting dialysis from 1970 through 1989: identification of risk factors for survival.

Survival estimates were performed on 683 chronic dialysis patients who started dialysis from 1970 through 1989 and followed through 1991. Patients were grouped by dialysis type, renal diagnosis, start-year group and age at start. During these 20 entry, years, the median starting age rose from 47 to 61 years. Patients with a renal diagnosis of diabetes mellitus or renal vascular disease increased to 41% of those starting dialysis during the last 8 years of study. Survival analysis for all of the 683 patients revealed a 51-month median survival and a 43% and 23% 5- and 10-year survival estimates, respectively. There was nearly a fourfold rise in the risk ratio as age increased from the youngest to oldest age groups. Home hemodialysis patients had the longest survival, 89% at 5 years; patients on CAPD had a 56% 5-year survival. In-center hemodialysis patients had a median survival of 48 months and a 5-year survival of 39%. Pairwise comparisons of the renal diagnostic groups found patients with polycystic kidneys, interstitial disease and chronic glomerulonephritis to have better survival than patients with diabetes mellitus, renal vascular disease or the "other" diagnoses (log-rank test, p < 0.001). Survival analyses showed age, renal diagnosis, race, type of dialysis and dialysis modality switch to be important predictors of survival. The results of the survival estimates, gross mortality rates and standardized mortality ratios were used as guides to the adequacy of dialysis and quality of care delivered for the years 1989 through 1992.

Age Factors↗

PubMed2002

Estimating survival gain for economic evaluations with survival time as principal endpoint: a cost-effectiveness analysis of adding early hormonal therapy to radiotherapy in patients with locally advanced prostate cancer.

The problem of estimating expected outcomes for the economic evaluation of treatments for which the outcome of principal interest is (quality adjusted) survival time has so far not received sufficient attention in the literature. The best estimate of expected survival is mean survival time, but with censored survival data, the true survival time for all the subjects is not known, so the mean is not defined.A possible solution to this estimation problem is illustrated by a retrospective cost-effectiveness analysis of the addition of hormonal therapy to standard radiotherapy for patients with locally advanced prostate cancer. A recently proposed method is used to approach the problem caused by censored cost data, and the impact of uncertainty is assessed by bootstrap resampling techniques. Mean survival time is estimated by a restricted means analysis with the time point of restriction determined by statistical criteria. When average total costs and mean survival time is evaluated at this time point of restriction, the result is that the combined therapy (radiotherapy plus hormonal therapy) increases mean survival time by about 1 year, while reducing the costs per patient for the French health insurance system by 12 700 FF. The time point of restriction may also be determined by other criteria and mean survival time may be estimated by extrapolating the survival curves by means of various parametric survival distributions. We show that the exact results of the economic evaluation are decisively determined by the restriction time point chosen and the approach taken to estimate mean survival time.

Antineoplastic Agents, Hormonal↗

PubMed2000

Correlation of clinical picture (event free survival and overall survival) in childhood acute leukemia patients with immunophenotype and chromosomal abnormalities.

In a group of 102 children with different immunological subtypes of acute leukemia, both lymphoblastic and nonlymphoblastic, the clinical parameters - event free survival and overall survival were correlated with numerical and structural chromosomal abnormalities. In a group of 80 ALL patients genetic abnormalities were observed in 40 patients, from those 19 of numerical type, 17 of structural type and 4 with both, numerical and structural anomalies. From the whole ALL group observed 23 patients (28.75%) died. In 10 died patients genetic abnormalities were found and in 6 cases less mature T-phenotype ALL has been documented. It seems, therefore, that immature T-phenotype with pathological karyotypes of all types of genetic anomalies presents the most risk group of patients of which all children died. ALL patients, as a whole, with pathological karyotype have shown significantly lower event free survival rate, comparing to the group of ALL patients with normal karyotype. Overall survival rate was also lower in the first group, but statistically not significant. In T-ALL patients, in both groups, with and without pathological karyotype, event free survival rate and overall survival rate were also lower in the first group, but statistically not significant. In B-ALL patients with pathological karyotypes vs. normal ones overall survival rate was lower in the first group, but statistically not significant. There was no difference in overall survival rate in these patients between pathological and normal karyotypes. In ANNL group of patients pathological karyotype was observed in 14 of them, with numerical anomalies in 6 patients, structural in 4 patients and both of them - numerical + structural in 4 children. From the whole ANLL group observed 11 (50%) patients died during the follow-up period (9 in relapse and 2 of treatment complications). From 11 died patients in 81.8% pathological karyotype was present. The prevalence of pathological karyotypes was observed in less mature M0-M2 ANLL subtype (71.4%). ANLL patients with pathological karyotype have shown significantly lower event free survival rate (in one of the two statistical log-rank analyses), comparing to the group of ANLL patients with normal karyotype. Overall survival rate was also lower in the first group, but statistically not significant. The presence/absence of CD34 marker expression in blast cells of our group of acute leukemia patients did not show any difference in event free survival and overall survival rates.

Adolescent↗

PubMed1992

Case and survival definitions in out-of-hospital cardiac arrest. Effect on survival rate calculation.

OBJECTIVE: To determine the effect of different case and survival definitions of out-of-hospital cardiac arrest on survival rate calculations. DESIGN: A 22-month case series of nontraumatic, out-of-hospital cardiac arrests. SETTING: Southwestern city (population, 400,000; area, 390 km2) with a two-tiered emergency response system consisting of emergency medical technicians and paramedics. PATIENTS: A consecutive sample of 372 patients found without palpable pulse of spontaneous respiration. MAIN OUTCOME MEASURES: Survival rate after cardiac arrest was calculated using three case definitions of arrest and two definitions of survival. RESULTS: Twenty percent of all patients survived to hospital admission and 6% survived to hospital discharge. Twenty-six percent of adults whose collapse was witnessed survived to hospital admission, and 10% survived to hospital discharge. Patients whose collapse was witnessed and who experienced initial ventricular fibrillation survived to hospital admission in 38% and to hospital discharge in 15% of cases. CONCLUSIONS: The survival rate after out-of-hospital cardiac arrest varies widely depending on the case and survival definitions selected. To facilitate intersystem comparison and assessment of interventions designed to improve outcome, the Utstein Consensus Conference recommended that case and survival definitions should be adopted by all prehospital emergency systems.

Aged↗

PubMed1991

Hyperthermic purging in vitro of murine leukemia cells (MK-8057): surviving fractions of normal and leukemic stem cells and the long-term survival of mice injected with the post-hyperthermic leukemia cells.

Hyperthermic purging of leukemic cells has been applied in clinical trials, although an accurate evaluation system to compare the effect on leukemia cells with that on normal hemopoietic cells has not been established. We evaluated the heat-sensitivity of murine leukemia cells, MK-8057, and compared differences in heat-sensitivity between surviving fractions of leukemic stem cells (leukemic spleen colony-forming units, L-CFU-S) and normal hemopoietic stem cells (spleen colony-forming units, CFU-S). Using the spleen colony assay, the survival fraction of L-CFU-S was compared with that of CFU-S after various hyperthermic treatments. One of the most efficient conditions, that is, hyperthermia at 42 degrees C for 3 h, allowed only 0.17% of L-CFU-S to survive, whereas 26.5% of normal CFU-S survived. Hyperthermia at 44 degrees C for 45 min further reduced the L-CFU-S (0.13%); however, the relative ratio of L-CFU-S to CFU-S was less than that at 42 degrees C for 3 h, because there was a larger reduction at 44 degrees C in normal CFU-S (5.1%). Recipient mice injected with MK-8057 cells treated with hyperthermia survived longer in proportion to the decreasing number of surviving L-CFU-S injected. This extension of the survival of recipient mice given MK-8057 cells after hyperthermia was also proportional to the estimated survival fraction of L-CFU-S. The survival fraction of MK-8057 cells after hyperthermia that was independently calculated through the extended survival of the recipients showed a good correlation with the surviving fraction of L-CFU-S, seen as the leukemic spleen colonies, at a correlation coefficient of r = 0.985. The number of surviving mice receiving the post-hyperthermic MK-8057 cells and the number of L-CFU-S calculated to have been injected had a relationship based on a Poisson distribution. Thus, the calculated results imply that the hyperthermia proportionally targets L-CFU-S, which are the only cells responsible for killing the recipient mice.

Animals↗

PubMed2004

Calculating microbial survival parameters and predicting survival curves from non-isothermal inactivation data.

Irrespective of whether the isothermal semi-logarithmic survival curves of heat inactivated microbial cells or spores are linear or nonlinear, it is theoretically possible to numerically calculate their survival parameters from inactivation data obtained under non-isothermal conditions. A method to do the calculation, when the temperature history ('profile') is expressed algebraically, is demonstrated with simulated survival curves. It has been tested with the published survival data of Salmonella, whose nonlinear semi-logarithmic isothermal survival curves can be described by a power law model. The reported survival ratios of Salmonella, determined during non-isothermal heat treatments in a broth and in ground chicken breast, were used to estimate its isothermal survival parameters in the two media and their temperature dependence. These, in turn, were used to predict the cells' survival curves under different temperature 'profiles.' There was a good agreement between the predicted and the reported experimental survival curves in the broth case and reasonable agreement in the ground chicken breasts, where the database was considerably smaller The development of a mathematical method to calculate survival parameters from non-isothermal inactivation data will eliminate the need to determine these parameters under isothermal conditions, which can only be approximated and are technically difficult to perform. In many cases, the proposed method will also enable the determination of the survival parameters in the actual food or medium of interest, which may contain particles, or is too viscous to be heated and cooled effectively using the currently available experimental procedures. In principle, the described mathematical method can also be used to assess organisms' survival parameters in nonthermal inactivation processes, such as exposure to a dissipating chemical agent or the application of ultra high-pressure.

Animals↗

PubMed2004

Providing more up-to-date estimates of patient survival: a comparison of standard survival analysis with period analysis using life-table methods and proportional hazards models.

OBJECTIVE: Standard survival methods can yield out-of-date estimates of long-term survival. Period analysis, based on life-table methodology, provides more up-to-date survival estimates by exploring survival during a restricted recent period of interest. It excludes the short-term survival of patients recruited at the start of the study. We use statistical models to further develop the method of period analysis, providing more up-to-date estimates of survival and the ability to explore differences in survival by covariates and adjust for case mix. METHODS: We use cancer registry data for colorectal cancer in Leicestershire, UK, to illustrate the use of Cox proportional hazards (CPH) models to estimate period and standard survival. We compare these estimates with those obtained using life-table methodology. RESULTS: Period estimates were slightly higher than the standard estimates as they reflect recent improvements in short-term survival. The results for period analysis using the life-table approach and using CPH models were similar. However, CPH models allowed further investigation of other risk factors and the ability to control for potential confounding variables. CONCLUSION: Using period survival estimates, more up-to-date information is available to clinicians and others with an interest in monitoring survival. Period CHP models offer all the advantages of statistical modeling, and are straightforward to fit in standard statistical packages.

Colorectal Neoplasms↗

PubMed2005

Patterns of graft and patient survival following renal transplantation and evaluation of serum creatinine as a predictor of survival: a review of data collected from one clinical centre over 34 years.

BACKGROUND: The pattern of renal transplantation has never been described since the introduction of the technique. The purpose of this study was therefore to characterise the pattern of renal transplantation from 1967 to 2000, focusing on renal graft function as a predictor of survival. METHODS: This study was a retrospective analysis of an electronic database. The setting was a single renal transplant centre in the United Kingdom covering a population of 2.2 million and included patients who received at least one renal transplant over the study period (n = 1516). The main outcome measures were patient and graft survival, acute rejection episodes and patterns of graft function, as measure by creatinine levels. RESULTS: There were 559 (36.8%) female patients; 109 (7.2%) patients had pre-existing diabetes. Patient survival was adversely affected by increased age at transplant (p < 0.001): 5-year patient survival from first transplant was 82% for patients aged 0 to 17 years, 80% for 18 to 49 years and 61% for > 49 years. Pre-existing diabetes also adversely affected survival (p < 0.01): 5-year graft survival was 63% for patients with diabetes versus 74% for those without. Graft survival was significantly associated with serum creatinine levels recorded 1 year post-primary transplant (p < 0.001) and with three or more acute rejection episodes (p < 0.05). Neither gender nor diabetes status were statistically significant in predicting graft survival. The number of acute rejection episodes was significantly greater in patients with pre-existing diabetes than those without (61% versus 42%, respectively; p < 0.001). There were no differences in the number of acute rejection episodes occurring across age groups. CONCLUSION: Patient and graft survival improved markedly over the 34-year study period, although patient survival has changed little since 1990. Serum creatinine levels are a reliable predictor of graft survival.

Adolescent↗

PubMed1999

Survival of Dicor glass-ceramic dental restorations over 14 years: Part I. Survival of Dicor complete coverage restorations and effect of internal surface acid etching, tooth position, gender, and age.

STATEMENT OF PROBLEM: There are no long-term data on Dicor glass-ceramic restoration survival in the human oral cavity and the effect that different technical and clinical variables have on survival. PURPOSE: This prospective study examined the relationship of different clinical parameters on the survival of Dicor glass-ceramic restorations in the human oral cavity. MATERIAL AND METHODS: A total of 417 subjects (from 17 to 91 years of age) participated. All subjects required single unit fixed prosthodontics in any area of the mouth and/or 3-unit fixed partial dentures or cantilevered anterior restorations. They were offered the option of a gold or conventional metal-ceramic restoration, or a Dicor restoration with potentially improved esthetic results, better wear characteristics, and diminished oral plaque accumulation. Overall survival of the restorations was determined and the effect of various clinical parameters evaluated with Kaplan-Meier survival curves. Log rank tests were used to determine statistically significant differences among parameters. RESULTS: For the 1444 units placed, 188 failures were recorded. Total time at risk for the units was 7319 years providing an estimated risk of 2.45% per year. Probabilities of survival of "typical" acid-etched Dicor and nonacid-etched Dicor restorations were 76% and 50%, respectively, at 14.1 years (P <.001). Probabilities of survival of typical acid-etched and nonacid-etched Dicor complete coverage restorations were virtually identical to those observed in the full data set. There was a 2.2 times greater risk of failure associated with the use of nonacid-etched Dicor complete coverage than acid-etched restorations (P <.01). Complete coverage restoration survival was highest in the incisor region and decreased to the molars in both arches. Second molars showed the highest failure rate. No complete coverage restorations failed on lateral incisors during the entire study. Probability of survival of a typical acid-etched Dicor complete coverage restoration in male subjects was 71%, and 75% for female subjects at 14.1 years (P <.01). The major difference appeared to be due to a greater failure rate in the maxillary arch of the male. Survivor functions of acid-etched Dicor complete coverage restorations for subjects in <33 years, 33 to 52 years, and 52 years age groups were 88% at 9 years, 62% at 14 years, and 82% at 14 years, respectively. CONCLUSIONS: Dicor restorations can survive successfully over time with certain reservations. Long-term survival improved significantly when restorations were acid-etched before luting. Complete coverage restoration failures per year decreased from molars to incisors in both arches, suggesting that complete coverage restorations on molars represented a serious risk. No Dicor complete coverage restoration on lateral incisors failed during the study. Restorations failed less often in female than male subjects.

Acid Etching, Dental↗