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Biomedical subjects

M Abrahamowicz

Publications and source records attributed to M Abrahamowicz.

At least 37 records · Page 2Linked to original sources
PubMed2001

Psychological distress, social support, and disease activity in patients with inflammatory bowel disease.

OBJECTIVES: The objectives of this study were to compare the psychological status of patients in active and inactive disease states, to assess social support, and to identify correlates of psychological distress in patients with inflammatory bowel disease (IBD). METHODS: This cross-sectional study was conducted in 200 patients (mean age 36.7 yr [SD = 14.8], 119 [59.5%] female) with long-standing IBD who were seen in tertiary care. Psychosocial assessments included psychological distress (Symptom Checklist-90R), social support (Social Support Questionnaire-6), perceived stress (Perceived Stress Scale-10), and recent minor stressful events (Weekly Stress Inventory). Disease activity was assessed with the Harvey Bradshaw Index. RESULTS: Patients reported higher levels of satisfaction with social support and smaller network sizes compared with normative values. Using multiple linear regression, the independent correlates of psychological distress (p = 0.0001; adjusted R2 = 0.62) were as follows: active disease (p = 0.0234), less time since diagnosis (p = 0.0012), and greater number (p = 0.0001) and impact of stressful events (p = 0.0003). A statistically significant interaction term (p = 0.0171) revealed that the relationship between psychological distress and perceived stress changes depending on the level of satisfaction with social support. For patients with low levels of perceived stress, satisfaction with social support did not affect levels of psychological distress. However, for patients who experienced moderate to high levels of perceived stress, high satisfaction with social support decreased the level of psychological distress. CONCLUSIONS: These findings suggest that strategies aimed at improving social support can have a favorable impact on psychological distress and, ultimately, can improve health outcomes in patients with IBD.

Adult↗
PubMed2001

Etiologic yield of autistic spectrum disorders: a prospective study.

At present, the etiologic yield in community-derived samples of young children with an autistic spectrum disorder is not known. To address this question, all young children (under 5 years of age) referred for an initial assessment to ambulatory pediatric neurology or developmental pediatric clinics at a tertiary university center over an 18-month period for a suspected developmental delay were prospectively identified. Specific diagnostic testing was left to the discretion of the evaluating physician. In all, 50 children with an autistic spectrum disorder were assessed. Detailed history or physical examination was informative with respect to suggesting the possibility of an underlying etiology in a minority (10/50,20%). Genetic studies (FMR-1, karyotype), electroencephalography (EEG), and neuroimaging were carried out in a majority (42/50, 34/50, and 33/50, respectively) of the children, for the most part on a screening rather than an indicated basis (31/42, 34/34, and 28/33, respectively). Etiologic yield was low (1/50, 2%), with only a single child identified with a possible Landau-Kleffner variant on sleep EEG tracing. The results suggest an evaluation paradigm with reference to etiologic determination for young children with autistic spectrum disorder that does not presently justify metabolic or neuroimaging on a screening basis. Recurrence risk and treatment implications, however, suggest that strong consideration be given to genetic (FMR-1, karyotype) testing and EEG study despite a relatively low yield.

Autistic Disorder↗
PubMed2001

Profile of referrals for early childhood developmental delay to ambulatory subspecialty clinics.

The objective of this study was to determine the profile and pattern of referral to subspecialty clinics of young children with suspected developmental delay together with the factors prompting their referral. All children under 5 years of age referred to either developmental pediatrics or pediatric neurology clinics at a single tertiary hospital over an 18-month period were prospectively identified. Standardized demographic and referral information were collected at intake, final developmental delay subtype diagnosed was identified, and referring physicians were surveyed regarding factors prompting referral. A total of 224 children met study criteria. There was a marked male preponderance (166/224), especially among those with either cognitive or language delay. Two delay subtypes, global developmental delay and developmental language disorder, accounted for two thirds of the diagnoses made. For slightly more than one third of the children (75/224), the delay subtype diagnosed following specialty evaluation was different from that initially suspected by the referring physician. A mean delay of 15.5 months was observed for the cohort as a whole between initial parental concern and specialty assessment. For referring physicians, the major factor prompting referral was the severity of the observed delay. The most important aspects of the specialty evaluation according to referral sources were the identification of a possible etiology and confirmation of delay. A profile of referrals and the rationale thereof for a cohort of children with suspected developmental delay is presented that, although locale specific, has implications for service provision and training.

Ambulatory Care↗
PubMed2001

A new and improved population-based Canadian reference for birth weight for gestational age.

BACKGROUND: Existing fetal growth references all suffer from 1 or more major methodologic problems, including errors in reported gestational age, biologically implausible birth weight for gestational age, insufficient sample sizes at low gestational age, single-hospital or other non-population-based samples, and inadequate statistical modeling techniques. METHODS: We used the newly developed Canadian national linked file of singleton births and infant deaths for births between 1994 and 1996, for which gestational age is largely based on early ultrasound estimates. Assuming a normal distribution for birth weight at each gestational age, we used the expectation-maximization algorithm to exclude infants with gestational ages that were more consistent with 40-week births than with the observed gestational age. Distributions of birth weight at the corrected gestational ages were then statistically smoothed. RESULTS: The resulting male and female curves provide smooth and biologically plausible means, standard deviations, and percentile cutoffs for defining small- and large-for-gestational-age births. Large-for-gestational age cutoffs (90th percentile) at low gestational ages are considerably lower than those of existing references, whereas small-for-gestational-age cutoffs (10th percentile) postterm are higher. For example, compared with the current World Health Organization reference from California (Williams et al, 1982) and a recently proposed US national reference (Alexander et al, 1996), the 90th percentiles for singleton males at 30 weeks are 1837 versus 2159 and 2710 g. The corresponding 10th percentiles at 42 weeks are 3233 versus 3086 and 2998 g. CONCLUSIONS: This new sex-specific, population-based reference should improve clinical assessment of growth in individual newborns, population-based surveillance of geographic and temporal trends in birth weight for gestational age, and evaluation of clinical or public health interventions to enhance fetal growth. fetal growth, birth weight, gestational age, preterm birth, postterm birth.

Algorithms↗
PubMed2000

Etiologic yield of subspecialists' evaluation of young children with global developmental delay.

OBJECTIVE: To determine the etiologic yield of subspecialists' evaluation of young children with global developmental delay. In addition, variables that may predict finding an underlying etiology were also identified. METHODS: All children <5 years of age, referred over an 18-month period to subspecialty services for initial evaluation of a suspected developmental delay, were prospectively enrolled. Diagnostic yield was ascertained after the completion of clinical assessments and laboratory investigations requested by the evaluating physician. RESULTS: Ninety-nine children (71 boys) were found to have global developmental delay; 96% had a mild or moderate delay documented. An etiologic diagnosis was determined in 44. Four diagnoses (cerebral dysgenesis, hypoxic-ischemic encephalopathy, toxin exposure, chromosomal abnormalities) accounted for 34 of 44 (77%) of the diagnoses made. The presence of co-existing autistic traits was associated with significantly decreased diagnostic yield (0/19 vs 44/80, P <.0001), whereas specific historical features (eg, family history, toxin exposure, and perinatal difficulty; 23/32 vs 21/67, P =.0002) and findings on physical examination (eg, dysmorphology, microcephaly, and focal motor findings; 35/48 vs 9/51, P <.0001) were significantly associated with identifying a diagnosis. Multiple logistic regression analysis identified antenatal toxin exposure, microcephaly, focal motor findings, and the absence of autistic traits as significant predictor variables for the identification of an etiology. CONCLUSION: An etiologic diagnosis is often possible in the young child with global developmental delay, particularly in the absence of autistic features. Etiologic yield is augmented by presence of specific findings on history or physical examination on initial assessment.

Autistic Disorder↗
PubMed2000

Etiologic yield of single domain developmental delay: a prospective study.

OBJECTIVE: To determine the etiologic yield in young children with single domain developmental delay (either developmental language disorder or isolated motor delay) after a specialty diagnostic evaluation. METHODS: During an 18-month period, all children <5 years of age, who were consecutively referred to pediatric neurology or developmental pediatric clinics at a single tertiary pediatric center, were prospectively enrolled. Etiologic yield was determined after completion of clinical assessments and selected laboratory studies requested by the evaluating physician. RESULTS: Seventy-two children (60 boys) were found to have a developmental language disorder, and 22 children (11 boys) had isolated motor delay, of whom 6 had an associated diagnosis of cerebral palsy. An etiologic diagnosis was rarely made in the children with developmental language disorder (3/72, 4.1%). Laboratory investigations (metabolic, cytogenetic, imaging), aside from audiometry, were uniformly uninformative. In those children with isolated motor delay, an etiology was apparent in more than half (13/22, 59%). Slightly more than half (7/13, 54%) of etiologies identified in this group were potentially preventable. Successful etiologic determination in children with motor delay often had an impact on recurrence risk estimation, medical management, or specific therapy offered (8/13, 62%). The presence of physical findings on initial assessment was found to be highly predictive of successful etiologic determination in children with isolated motor delay (13/17 vs 0/5, P =.002). CONCLUSION: Etiologic yield differs substantially according to the subgroup of single domain developmental delay.

Cerebral Palsy↗
PubMed2000

Time-dependence of survival predictions based on markers of HIV disease. Swiss HIV Cohort Study.

OBJECTIVE: To determine whether the ability of baseline clinical stage, viremia, and CD4 cell counts to predict mortality in HIV-1-infected patients changes with duration of follow-up. METHODS: Three hundred ninety-four patients were followed for an average of 29 months by the Swiss HIV Cohort Study, a practice-based registry of HIV-1-infected patients in Switzerland. Predictor variables were the baseline clinical stage, CD4 cell count, circulating HIV-1 RNA level, and the RNA/CD4 ratio; the outcome was death. The changes in relative risks of death over time were examined using survival models that extend the Cox model to allow for nonproportionality of hazards. RESULTS: During 949 person-years of follow-up, 169 patients died (mortality rate 17.8 per 100 person-years). Compared with clinical stage A, patients in stages B and C at baseline had much higher mortality rates in the subsequent year. The prognostic ability of stage C decayed over time (P = 0.03). By contrast, the relative risks associated with a 2-fold difference in CD4 counts remained remarkably stable, at approximately 0.6 (P = 0.81 for the time-dependence test). Relative hazards associated with a 10-fold difference in HIV RNA per milliliter and in HIV RNA per CD4 cell both tended to increase over time, but this trend failed to reach statistical significance (P = 0.21 and P = 0.08, respectively). CONCLUSIONS: Time-dependence patterns of prognostic ability varied widely among predictors, displaying gradual decay (clinical stage), stability (CD4 cells), and a trend to progressive increase (viremia). These results may affect clinical monitoring of HIV-infected patients and the interpretation of cohort studies of HIV-infected patients.

Adolescent↗
PubMed2000

Do lupus disease activity measures detect clinically important change?

OBJECTIVE: New scales for the clinical assessment of patients with systemic lupus erythematosus (SLE) are valid and reliable, and quantitate disease activity. We assessed the responsiveness to change of 2 widely used standardized multi-item lupus activity measures, the revised Systemic Lupus Activity Measure (SLAM-R) and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and their ability to detect clinically relevant changes. METHODS: Ninety-six (96) patients with definite SLE participated in this study. The group mean age was 45.0 (13.7) years, 91% were female, and the mean disease duration was 14.9 (7.5) years. Sociodemographic information, lupus activity (SLAM-R, SLEDAI), and damage were recorded at baseline. At each of the 5 monthly followup visits, the activity measures were repeated and a transition scale asked the physician if their patient's lupus activity had changed. Five different methods were used to compare the responsiveness of the activity measures studied: 1. the effect size; 2. the standardized response mean; 3. the control standardized response mean; 4. the area under the curve of a receiver operating characteristic (ROC) curve; and 5. a new multiple response modeling approach. RESULTS: Both SLAM-R and SLEDAI are responsive. SLAM-R is consistently, although moderately, more responsive than SLEDAI. All 5 methods of evaluating responsiveness yielded a consistent ranking of disease activity measures. CONCLUSION: SLAM-R and SLEDAI are responsive measures of lupus activity. SLAM-R appears to be more responsive than SLEDAI.

Activities of Daily Living↗
PubMed1999

Variation over time of the effects of prognostic factors in a population-based study of colon cancer: comparison of statistical models.

The authors compare the performance of different regression models for censored survival data in modeling the impact of prognostic factors on all-cause mortality in colon cancer. The data were for 1,951 patients, who were diagnosed in 1977-1991, recorded by the Registry of Digestive Tumors of Côte d'Or, France, and followed for up to 15 years. Models include the Cox proportional hazards model and its three generalizations that allow for hazard ratio to change over time: 1) the piecewise model where hazard ratio is a step function; 2) the model with interaction between a predictor and a parametric function of time; and 3) the non-parametric regression spline model. Results illustrate the importance of accounting for non-proportionality of hazards, and some advantages of flexible non-parametric modeling of time-dependent effects. The authors provide empirical evidence for the dependence of the results of piecewise and parametric models on arbitrary a priori choices, regarding the number of time intervals and specific parametric function, which may lead to biased estimates and low statistical power. The authors demonstrate that a single, a priori selected spline model recovers a variety of patterns of changes in hazard ratio and fits better than other models, especially when the changes are non-monotonic, as in the case of cancer stages.

Aged↗
PubMed1999

Screening mammography referral rates for women ages 50 to 69 years by recently-licensed family physicians: physician and practice environment correlates.

BACKGROUND: Physician mammography referral remains below optimal levels despite a long-standing recommendation that all women ages 50 to 69 years receive screening mammography every 1 to 2 years. The purpose of this study was to determine physician and practice environment predictors of family physicians' screening mammography referral rates to women ages 50-69 years. METHOD: A cohort of 498 recently-licensed family physicians was followed for 18-months of incipient medical practice. The referral rate was the percentage of new clinically eligible women patients seen in a primary care context who had a screening mammogram ordered by the study physician. Mammograms and independent variables were identified from physician claims to a Canadian universal health insurance agency. The effects of factors in a conceptual framework were assessed using multivariable linear regression. RESULTS: Correlates of higher mammography referral rates were female gender, better general prevention knowledge, the combination of comprehensive inquiry and continuity care, lower patient volume, and lower shared primary care (multivariable model R(2) = 0.47). Factors belonging to practice environment explained more of the observed variance than did physician characteristics. CONCLUSIONS: Mammography referral varies enormously and almost half of the variance is explained by physician characteristics and practice preferences. Higher mammography referral is observed in practices with more comprehensive and continuity care.

Adult↗
PubMed1999

Testing the proportional hazards assumption in medical survival studies--application to a population-based study of acute myeloid leukaemia.

BACKGROUND: In the analysis of survival data using the Cox proportional hazard model, it is assumed that the magnitude of mortality risk for a predictor variable remains proportional over time. The time-dependent linear model and the piece-wise proportional hazard model (two or four intervals) take into account the variation of the risk over the entire follow-up period. METHOD: The three existing models were applied to a series of 266 patients with acute myeloid leukaemia (AML), diagnosed between 1980 and 1992 and recorded by the Registry of Hematopoietic Neoplasms in Côte d'Or, France. RESULTS: A non-proportional effect of age, period of diagnosis, whether the illness was primary or secondary and French-American-British (FAB) subtype was found significant. In particular, the effect of M2 versus M4-M5 subtypes was revealed by the non-proportional analyses, although this effect was non-significant using the Cox model. CONCLUSIONS: The clinical explanation of the variation of these effects over time is discussed, for example, relating the increase over time of the positive effect of the period of diagnosis to therapeutic improvements. Confirmation of these results on an independent data set is required.

Acute Disease↗
PubMed1998

Evaluation of rubella screening in pregnant women.

BACKGROUND: The rationale for rubella vaccination in the general population and for screening for rubella in pregnant women is the prevention of congenital rubella syndrome. The objective of this study was to evaluate the effectiveness of the prenatal rubella screening program in Quebec. METHODS: A historical cross-sectional study was designed. Sixteen hospitals with obstetric services were randomly selected, 8 from among the 35 "large" hospitals in the province (500 or more live births/year) and 8 from among the 50 "small" hospitals (fewer than 500 live births/year). A total of 2551 women were randomly selected from all mothers of infants born between Apr. 1, 1993, and Mar. 31, 1994, by means of stratified 2-stage sampling. The proportions of women screened and vaccinated were ascertained from information obtained from the hospital chart, the physician's office and the patient. RESULTS: The overall (adjusted) screening rate was 94.0%. The rates were significantly different between large and small hospitals (94.4% v. 89.6%). Five large hospitals and one small hospital had rates above 95.0%. The likelihood of not having been screened was statistically significantly higher for women who had been pregnant previously than for women pregnant for the first time (4.8% v. 1.4%; p < 0.001). Of the 200 women who were seronegative at the time of screening (8.4%), 79 had been vaccinated postpartum, had a positive serological result on subsequent testing or did not require vaccination, and 59 had not been vaccinated postpartum; for 62, subsequent vaccination status was unknown. INTERPRETATION: Continued improvement in screening practices is needed, especially in small hospitals. Because vaccination rates are unacceptably low, it is crucial that steps be taken to address this issue.

Canada↗
PubMed1998

Association between licensing examination scores and resource use and quality of care in primary care practice.

CONTEXT: Clinical competence is a determinant of the quality of care delivered, and may be associated with use of health care resources by primary care physicians. Clinical competence is assumed to be assessed by licensing examinations, yet there is a paucity of information on whether scores achieved predict subsequent practice. OBJECTIVE: To determine if licensing examination scores were associated with selected aspects of quality of care and resource use in initial primary care practice. DESIGN: Prospective cohort study of recently licensed family physicians, followed up for the first 18 months of practice. SETTING: The Quebec health care system. PARTICIPANTS: A total of 614 family physicians who passed the licensing examination between 1991 and 1993 and entered fee-for-service practice in Quebec. MAIN OUTCOME MEASURES: All patients seen by physicians were identified by the universal health insurance board and all health services provided to these patients were retrieved for the 18 months prior to (baseline) and after (follow-up) the physicians' entry into practice. Medical service and prescription claims files were used to measure rates of resource use (specialty consultation, symptom-relief prescribing compared with disease-specific prescribing) and quality of care (inappropriate prescribing, mammography screening). Baseline data were used to adjust for differences in practice population. RESULTS: Study physicians saw a total of 1116389 patients, of whom 113535 (10.2%) were elderly and 83391 (7.5%) were women aged 50 to 69 years. Physicians with higher licensing examination scores referred more of their patients for consultation (3.8/1000 patients per SD increase in score; 95% confidence interval [CI], 1.2-7.0; P = .005), prescribed to elderly patients fewer inappropriate medications (-2.7/1000 patients per SD increase in score; 95% CI, -4.8 to -0.7; P=.009) and more disease-specific medications relative to symptom-relief medications (3.9/1000 patients per SD increase in score; 95% CI, 0.3 to 7.4; P= .03), and referred more women aged 50 to 69 years (6.6/1000 patients per SD increase in score; 95% CI, 1.2-11.9; P = .02) for mammography screening. If patients of physicians with the lowest scores had experienced the same rates of consultation, prescribing, and screening as patients of physicians with the highest scores, an additional 3027 patients would have been referred, 179 fewer elderly patients would have been prescribed symptom-relief medication, 912 more elderly patients would have been prescribed disease-specific medication, 189 fewer patients would have received inappropriate medication, and 121 more women would have received mammography screening. CONCLUSIONS: Licensing examination scores are significant predictors of consultation, prescribing, and mammography screening rates in initial primary care practice.

Adult↗
PubMed1998

Does hepatitis C virus co-infection accelerate clinical and immunological evolution of HIV-infected patients?

OBJECTIVE: To study the influence of hepatitis C virus (HCV) co-infection on clinical and immunological evolution of HIV-infected patients. DESIGN: A longitudinal study of HIV-infected individuals with or without HCV infection, identified at the Infectious Diseases Department of Dijon University Hospital and enrolled in a historical cohort, was performed. METHODS: One hundred and nineteen HIV-infected people co-infected with HCV and 119 matched individuals infected with HIV alone were included in the cohort (median participation time 3 years; range, 2 months to 11.5 years). Clinical progression was defined as one or more of the following: a 30% decrease in the Karnofsky index; a 20% loss of body weight; an AIDS-defining illness (for non-AIDS patients); death (except by accident, suicide or overdose). Immunological progression was defined as a 50% decrease in the initial CD4 T-cell count (for patients with an initial count > 100 x 10(6) cells/l). Effects of HCV co-infection were evaluated using Kaplan-Meier survival analysis and significance was tested using univariate (log-rank and Peto's tests) and multivariate methods (Cox's model). RESULTS: In univariate analysis, immunological progression was not statistically different between the HCV-positive group and the HCV-negative group, whereas clinical progression was significantly faster in HCV-positive patients (P < 0.005, log-rank test). In a multivariate Cox model, clinical progression remained significantly associated with infection by HCV [hazard ratio (HR), 1.64; 95% confidence interval (CI), 1.06-2.55; P < 0.05]. Stratified multivariable analysis retained HCV as a significant prognostic factor of clinical progression (HR, 10.9; 95% CI, 1.09-109.3; P < 0.05) and immunological progression (HR, 2.31; 95% CI, 1.16-4.62; P < 0.02) for patients with an initial CD4 count above 600 x 10(6) cells/l. CONCLUSIONS: Clinical progression is more rapid in HIV-HCV co-infected patients than in HIV-seropositive patients are not infected by HCV. The prognostic value of HCV infection for both clinical and immunological progression is significant at early stages of HIV infection. These findings may argue for active management of hepatitis C infection in co-infected individuals, especially for asymptomatic patients whose CD4 count is above 600 x 10(6) cells/l, to predict and prevent accelerated progression of HCV and HIV diseases.

Adult↗
PubMed1998

Effect of splenectomy on slowing human immunodeficiency virus disease progression.

BACKGROUND: Lymphoreticular tissue is the most important site for human immunodeficiency virus (HIV) replication in HIV-infected individuals. OBJECTIVE: To compare the long-term effect of splenectomy on survival and time to development of acquired immunodeficiency syndrome in subjects who had undergone splenectomy with subjects who had not undergone splenectomy. DESIGN: A cohort study with a follow-up of up to 13.4 years. SETTING: Subjects were recruited from a hospital outpatient clinic population and a multicenter study of patients with hemophilia. PARTICIPANTS: Forty-five HIV-infected individuals were observed prospectively for up to 13.4 years (17 had undergone splenectomy and 28 had not undergone splenectomy). Five subjects underwent splenectomy before acquiring HIV infection and 12 underwent splenectomy during the asymptomatic phase of HIV infection. The group who did not undergo splenectomy consisted of HIV-infected individuals who were asymptomatic at study enrollment. MAIN OUTCOME MEASURES: A Cox proportional hazards model was used to test the effects of splenectomy on survival and time to development of acquired immunodeficiency syndrome when adjusting for potential confounders (age, initial CD4+ cell count, and treatment with antiretroviral drugs). Splenectomy was treated as a time-dependent covariate to account for the variation in its timing. RESULTS: During the average follow-up of 8.6 years, 9 (53%) of the 17 subjects who underwent splenectomy and 23 (82%) of the 28 subjects who did not undergo splenectomy died; acquired immunodeficiency syndrome developed in 6 (35%) of the subjects who underwent splenectomy and 23 (82%) of the subjects who did not undergo splenectomy. Splenectomy was associated with a significant reduction of risk of developing acquired immunodeficiency syndrome (adjusted relative risk [RR] <0.4, P<.05), whereas the effect on risk of mortality approached, although it did not reach, significance (adjusted RR approximately 0.5, P approximately .10). CONCLUSION: The absence of a spleen during the asymptomatic phase of HIV infection seems to have a beneficial effect on HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Normal distributions of thermal and vibration sensory thresholds.

The distributions of sensory thresholds were estimated in a healthy population while controlling for potential covariates. Using the method of levels and the two-alternative forced choice, thermal and vibration thresholds respectively were measured in the hand and foot of 148 subjects. Age was uniformly distributed between 20 and 86 years. Independent effects of age, gender, height, and skin temperature were estimated using multiple linear regression. Parametric and nonparametric methods were used to estimate the distributions of interest. Significant age-related increases were observed for all vibration thresholds (P < 0.0001), and for thermal thresholds in the foot (P < 0.0002). Percentiles were estimated for thermal thresholds in the hand and age-adjusted continuous distributions were calculated for all other thresholds. Height was positively associated with vibration thresholds in the foot (P < 0.003), and appropriate corrections were made. Our results provide reference values for thermal and vibration sensory thresholds in a healthy population, allowing for the accurate diagnosis of disordered sensory function.

Adult↗