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PubMed1992

The impact of changing BCG coverage on tuberculosis incidence in Swedish-born children between 1969 and 1989.

In April 1975, the mass vaccination of newborns against tuberculosis was replaced by selective vaccination of groups at risk. BCG coverage fell from more than 95% before 1974 to 1.8% between 1975 and 1982 and thereafter reached an average of 13.7% up to 1989. The cumulative incidence of tuberculosis before 5 years of age was estimated among children born in Sweden during periods of high, low and moderate increasing BCG coverage. The incidence figures per 100,000 children was 0.8, 3.9 and 2.9, respectively, for children born to Swedish parents and 2.6, 39.4 and 13.2, respectively, for those born to foreign parents. The observed incidence of tuberculosis among non-BCG vaccinated children born to Swedish parents was within the expected limits given by a prognostic model based on the natural change of the risk of infection. The effectiveness of the selective BCG vaccination programme, which was intensified after 1981 for the second generation of immigrants, was estimated to 0.82 (95% confidence interval 0.38, 0.95) assuming that there was no change of the risk of infection for children born to foreign parents over the period studied. From April 1975 to December 1989, tuberculosis was notified in 85 children born in Sweden during the same period, 7 of them were BCG vaccinated and 78 non-vaccinated, 45 were symptomatic, 3 of them with disseminated tuberculosis.

Adolescent↗

PubMed2004

Measuring performance in health care: case-mix adjustment by boosted decision trees.

OBJECTIVE: The purpose of this paper is to investigate the suitability of boosted decision trees for the case-mix adjustment involved in comparing the performance of various health care entities. METHODS: First, we present logistic regression, decision trees, and boosted decision trees in a unified framework. Second, we study in detail their application for two common performance indicators, the mortality rate in intensive care and the rate of potentially avoidable hospital readmissions. RESULTS: For both examples the technique of boosting decision trees outperformed standard prognostic models, in particular linear logistic regression models, with regard to predictive power. On the other hand, boosting decision trees was computationally demanding and the resulting models were rather complex and needed additional tools for interpretation. CONCLUSION: Boosting decision trees represents a powerful tool for case-mix adjustment in health care performance measurement. Depending on the specific priorities set in each context, the gain in predictive power might compensate for the inconvenience in the use of boosted decision trees.

Decision Trees↗

PubMed2006

Long-term results of autologous stem cell transplantation for primary refractory or relapsed Hodgkin's lymphoma.

Autologous hematopoietic stem cell transplantation (ASCT) has become standard therapy for primary refractory (PR REF) or relapsed (REL) Hodgkin's lymphoma (HL); however, more than half of these patients eventually relapse and die of their disease. We studied long-term outcomes and evaluated factors influencing progression-free survival (PFS) in 141 patients with PR REF or REL HL who underwent ASCT between 1985 and 2003. Median age at ASCT was 30 years (range, 7-60 years); 21 patients had PR REF, and 120 had REL HL. With a median follow-up of 6.3 years (range, 1-20 years), the probability of PFS at 5 and 10 years was 48% (95% confidence interval [CI], 39%-57%) and 45% (95% CI, 36%-54%) and that of overall survival (OS) was 53% (95% CI, 44%-62%) and 47% (95% CI, 37%-57%), respectively. Transplant-related mortality at 100 days was 1.4%. Among 45 5- to 20-year survivors, no late relapses of HL were observed. In multivariate analysis, 3 factors were independently predictive of poor PFS: chemoresistant disease (relative risk [RR], 2.9; 95% CI, 1.7-5.0), B-symptoms at pretransplantation relapse (RR, 2.1; 95% CI, 1.3-3.4), and presence of residual disease at the time of transplantation (RR, 2.3; 95% CI, 1.1-4.8). Patients with 0 or 1 of these 3 adverse factors (low-risk disease) had a 5-year PFS of 67% (95% CI, 55%-79%) compared with 37% (95% CI, 22%-52%) in those with 2 factors (intermediate-risk group) and 9% (95% CI, 0-20%) in those with all 3 factors (high-risk group) (P < .001). The rates of OS at 5 years were 71% (95% CI, 60%-82%), 49% (95% CI, 33%-65%) and 13% (95% CI, 0-27%) in the 3 groups, respectively (P < .001). ASCT is associated with durable PFS in appropriately selected patients with PR REF or REL HL. Using a simple prognostic model, we can identify patients with high-risk disease who have predictably unfavorable outcome after ASCT and require novel therapeutic approaches. A risk-adapted approach should be followed in determining treatment options for patients with PR REF and REL HL.

Adolescent↗

PubMed2006

Molecular subclasses of high-grade glioma predict prognosis, delineate a pattern of disease progression, and resemble stages in neurogenesis.

Previously undescribed prognostic subclasses of high-grade astrocytoma are identified and discovered to resemble stages in neurogenesis. One tumor class displaying neuronal lineage markers shows longer survival, while two tumor classes enriched for neural stem cell markers display equally short survival. Poor prognosis subclasses exhibit markers either of proliferation or of angiogenesis and mesenchyme. Upon recurrence, tumors frequently shift toward the mesenchymal subclass. Chromosomal locations of genes distinguishing tumor subclass parallel DNA copy number differences between subclasses. Functional relevance of tumor subtype molecular signatures is suggested by the ability of cell line signatures to predict neurosphere growth. A robust two-gene prognostic model utilizing PTEN and DLL3 expression suggests that Akt and Notch signaling are hallmarks of poor prognosis versus better prognosis gliomas, respectively.

Biomarkers, Tumor↗

PubMed2005

Outcome of salvage radiotherapy for biochemical failure after radical prostatectomy with or without hormonal therapy.

BACKGROUND: This study analyzed the outcome of salvage radiotherapy for biochemical failure after radical prostatectomy (RP). By comparing the outcomes for patients who received RT alone and for those who received combined RT and hormonal therapy, we assessed the potential benefits of hormonal therapy. PATIENTS AND METHODS: This cohort was comprised of 101 patients who received salvage RT between 1990 and 2001 for biochemical failure after RP. Fifty-nine of these patients also received hormone. Margin status (positive vs. negative), extracapsular extension (yes vs. no), seminal vesicle involvement (yes vs. no), pathologic stage, Gleason score, pre-RP PSA, post-RP PSA, pre-RT PSA, hormonal use, radiotherapy dose and technique, RP at M. D. Anderson Cancer Center, and time from RP to salvage RT were analyzed. Statistically significant variables were used to construct prognostic groups. RESULTS: Independent prognostic factors for the RT-alone group were margin status and pre-RT PSA. RP at M. D. Anderson Cancer Center was marginally significant (p = 0.06) in multivariate analysis. Pre-RT PSA was the only significant prognostic factor for the combined-therapy group. We used a combination of margin status and pre-RT PSA to construct a prognostic model for response to the salvage treatment based on the RT group. We identified the favorable group as those patients with positive margin and pre-RT PSA < or = 0.5 ng/mL vs. the unfavorable group as otherwise. This stratification separates patients into clinically meaningful groups. The 5-year PSA control probabilities for the favorable vs. the unfavorable group were 83.7% vs. 61.7% with radiotherapy alone (p = 0.03). Androgen ablation seemed to be most beneficial in the unfavorable group. CONCLUSION: After prostatectomy, favorable-group patients may fare well with salvage radiotherapy alone. These patients may be spared the toxicity of androgen ablation. The other patients may benefit most from a combined approach with hormonal treatment. We further suggest that salvage radiotherapy should be given early when the PSA is still low.

Adult↗

PubMed2004

A nested case-control study of influenza vaccination was a cost-effective alternative to a full cohort analysis.

OBJECTIVE: In the absence of trial results that are applicable to the target population, nested case-control studies might be an alternative to full-cohort analysis. We compared relative and absolute estimates of associations in an influenza vaccine study using both designs. STUDY DESIGN AND SETTING: Data from elderly persons enrolled during six consecutive influenza seasons were used (147,551 person-periods). The endpoints "hospitalization for pneumonia or influenza" (P&I) or "death" were used combined and separately to define three types of cases. Controls for the case-control samples were randomly selected from the remainder of the total cohort at different ratios (1:1 to 1:4). Logistic regression analysis was used to assess adjusted vaccine effectiveness (VE). Sampling fractions were used to determine the number needed to treat to prevent one outcome. Receiver-operator-curve analysis was conducted to estimate the area under the curve (AUC) as a measure of discriminative capacity of the prognostic model. RESULTS: In all, 978 P and I hospitalizations and 1,339 deaths were observed. The adjusted estimates of relative estimates (VE, AUC) and their corresponding 95% confidence intervals were virtually the same using both study designs, notably when the case-control ratio was high (1:4). CONCLUSION: A nested case-control design can provide valid and precise estimates of associations and is a cost-effective alternative for full-cohort analysis.

Aged↗

PubMed2007

Improved survival with pulmonary metastasectomy: an analysis of 1720 patients with pulmonary metastatic melanoma.

OBJECTIVES: The outcomes of patients with metastatic melanoma are poor. Although prognostic models have been developed to predict the occurrence of pulmonary metastasis from cutaneous melanoma, few data exist to define the outcomes of these patients once metastasis has occurred. The objective of this study was to discriminate predictors of survival for patients with pulmonary metastatic melanoma. METHODS: We found 1720 patients with pulmonary metastasis listed in a prospective comprehensive cancer center database of 14,057 consecutive patients with melanoma (Jan 1, 1970-June 1, 2004). Demographic and histopathologic data, time and location of recurrences, number of pulmonary nodules, and subsequent therapies were collected. Univariate and multivariate Cox proportional hazards models were used to identify predictors of survival for patients with pulmonary metastatic melanoma. RESULTS: The median survival was 7.3 months after development of pulmonary metastasis. Significant predictors of survival from the multivariate model included nodular histologic type (P = .033), disease-free interval (P < .001), number of pulmonary metastases (P = .012), presence of extrathoracic metastasis (P < .001), and performance of pulmonary metastasectomy (P < .001). Interactions were identified between metastasectomy and disease-free interval and presence of extrathoracic metastasis. Surgery was associated with a survival advantage of 12 months for patients with a disease-free interval longer than 5 years (19 vs 7 months, P < .01) and of 10 months for patients without extrathoracic metastasis (18 vs 8 months, P < .01). CONCLUSIONS: When all other identified risk factors were controlled for mathematically, metastasectomy maintained a significant survival advantage for patients with pulmonary metastatic melanoma. These data support the role of surgery for a select subset of patients with pulmonary metastasis.

Disease-Free Survival↗

PubMed2004

Prognostic factors for neck pain in general practice.

Prognostic studies on neck pain are scarce and are typically restricted to short-term follow-up only. In this prospective cohort study, indicators of short- and long-term outcomes of neck pain were identified that can easily be measured in general practice. Patients between 18 and 70 years of age, suffering for at least 2 weeks from neck pain were recruited by 42 general practitioners (GPs). Perceived recovery, pain intensity and neck dysfunction after 7 and 52 weeks were considered as outcome measures. Indicators of prognosis were identified by means of logistic regression analyses (perceived recovery) and linear regression analyses (pain intensity and neck dysfunction). In total, 183 patients were included. After 1 year, 63% had recovered. The prognostic models showed differences between short- and long-term indicators. At the short term, besides the baseline values of the respective outcome measurements, only older age (> or =40) and concomitant low back pain and headache were associated with poor outcome. At the long term, in addition to age and concomitant low back pain, previous trauma, a long duration of neck pain, stable neck pain during the 2 weeks prior to baseline measurement, and previous neck pain predicted poor prognosis. The predictive power of the models was weak: the explained variance (R(2)) varied from 24 to 36%. Patient history and physical examination give GPs little handholds to predict the prognosis for patients with sub-acute and chronic neck pain. A few indicators of a less favourable prognosis of neck pain were identified, of which older age and concomitant low back pain was the most consistent.

Adolescent↗

PubMed2005

Prognostic factors for poor recovery in acute whiplash patients.

The objective of our prospective inception cohort study was to identify prognostic factors for poor recovery in patients with whiplash-associated disorders grade 1 or 2 who still had neck pain and accompanying complaints 2 weeks after the accident. The study was carried out in a primary health care setting in The Netherlands and included 125 patients. The primary outcome measure was functional recovery defined in terms of neck pain intensity or work disability without medication use. The secondary outcome measures included neck pain intensity, work disability and sick leave. The outcomes were assessed at 4, 12 and 52 weeks after the accident. Prognostic factors were identified by logistic regression analyses. One year after the injury, 64% of the patients were recovered. Factors related to poor recovery were female gender, a low level of education, high initial neck pain, more severe disability, higher levels of somatisation and sleep difficulties. Neck pain intensity and work disability proved to be the most consistent predictors for poor recovery. The accuracy of the predictions of the prognostic models was high, meaning that the models adequately distinguished patients with poor recovery from those regarded as recovered. These findings add to the growing body of evidence, indicating that socio-demographic, physical and psychological factors affect short- and long-term outcome after whiplash injury. Our findings also indicate that care providers can easily identify patients at risk for poor recovery with a visual analogue scale for initial pain intensity and work-related activities.

Acute Disease↗

PubMed2001

Predicting the sites of metastases from lung cancer using molecular biologic markers.

BACKGROUND: The use of molecular markers in staging non-small cell lung cancer (NSCLC) has been supported in retrospective prognostic models but has not been evaluated in predicting sites of metastases. METHODS: Pathologic specimens were collected from 202 patients after complete resection for stage I NSCLC, who were subsequently found to have no metastases at 5 years (n = 108), isolated brain metastases (n = 25), or other distant metastases (n = 69). A panel of eight molecular markers of metastatic potential was chosen for immunohistochemical analysis of the tumor: p53, erbB2, angiogenesis factor viii, EphA2, E-cadherin, urokinase plasminogen activator (UPA), UPA receptor, and plasminogen activator inhibitor. RESULTS: Patients with isolated brain relapse had significantly higher expression of p53 (p = 0.02) and UPA (p = 0.002). The quantitative expression of E-cadherin was used to predict the site of metastases using recursive partitioning: 0 of 92 patients with E-cadherin expression of 0, 1, or 2 developed isolated cerebral metastases; 0 of 33 patients with E-cadherin expression of 3 with UPA of 1 or 2 and ErbB2 of 0 developed brain metastases. Of the remaining patients at risk (UPA = 3), the risk of isolated cerebral metastases was 21 of 57 patients (37%). CONCLUSIONS: This study demonstrates that molecular markers may predict the site of relapse in early stage NSCLC. If validated in an ongoing prospective study, these results could be used to select patients with isolated brain metastases for adjuvant therapy, such as prophylactic cranial irradiation.

Biomarkers, Tumor↗

PubMed1995

Can overall results of clinical trials be applied to all patients?

It is generally assumed that the overall results of a clinical trial are generalisable to all patients in the trial and all similar future patients; in other words, that the relative treatment effect in individual patients is similar to the overall trial result. Although this assumption underpins the application of trial results to clinical practice, it has rarely been tested. By independently derived prognostic models, the results of the European Carotid Surgery Trial and the UK-TIA Aspirin Trial were reanalysed to find out whether relative treatment effect varied with absolute baseline risk of stroke. There was significant heterogeneity of relative treatment effect in both trials, resulting in substantial variation in absolute treatment effect with predicted baseline risk. Although, on average, the application of overall trial results to all patients will do more good than harm, a knowledge of the association between relative treatment effect and absolute baseline risk will increase the cost-effectiveness of healthcare interventions by identifying those patients in whom treatment is ineffective and those patients who are most likely to benefit.

Aspirin↗

PubMed1998

A long term follow-up of a randomized trial comparing interferon-alpha with busulfan for chronic myelogenous leukemia. The Kouseisho Leukemia Study Group.

To evaluate the long-term effectiveness of interferon-alpha (IFN-alpha) therapy in patients with chronic myelogenous leukemia (CML) in chronic phase, we examined the updated outcomes of 159 patients who had been enrolled between 1988 and 1991 into a randomized trial comparing IFN-alpha with busulfan. At a median follow-up of 73 months, the median survival was 71 months in the IFN-alpha group and 55 months in the busulfan group (P=0.0563), and the median time of remaining in chronic phase was 58 months in the IFN-alpha group and 39 months in the busulfan group (P=0.4676). Landmark analysis showed a significant advantage in survival (P=0.009) and duration of chronic phase (P=0.0001) in patients with any cytogenetic response among the IFN-alpha group. About half patients were discontinued IFN-alpha administration in spite of cytogenetic response in this study. It appears that continuation of IFN-alpha might possibly confer a survival advantage. Pretreatment factors associated with cytogenetic response included high hemoglobin level, low percentage of peripheral basophils and low leukocyte counts. Multivariate analysis identified lower percentage of bone marrow basophilia (P=0.007) for survival advantage. If a group with a very good prognosis is predicted by a new prognostic model, it might be an option to wait for bone marrow transplantation.

Adult↗

PubMed2001

Autoantibodies against nuclear pore complexes are associated with more active and severe liver disease in primary biliary cirrhosis.

BACKGROUND/AIMS: Antibodies against nuclear pore complexes (NPCs) have been detected in primary biliary cirrhosis (PBC), but their clinical relevance is still unsettled. METHODS: We tested sera from 171 consecutive PBC patients and 230 control subjects (149 with autoimmune or viral liver diseases, 28 with systemic lupus erythematosus, and 53 healthy) by immunoblotting for antibodies against purified human NPCs. RESULTS: Antibodies to NPCs were detected in 27% of the patients with PBC, were highly specific (97%), and were not associated with antimitochondrial antibodies. Their prevalence was higher in symptomatic patients (36 vs. 16%, P < 0.01) and was associated (P < 0.001) with more severe disease, as assessed by the presence of cirrhosis or its complications (13% prevalence in patients without cirrhosis, 31% in uncomplicated, and 54% in complicated cirrhosis), or by the application of the Mayo prognostic model (12% in the lowest, 21% in the median, 47% in the highest score tertile). Positive patients had higher levels of serum bilirubin (2.2 +/- 3.7 vs. 1.0 +/- 1.1 mg/dl, P < 0.01) and more marked inflammatory infiltrates on liver biopsy (P < 0.05). CONCLUSIONS: Autoantibodies to NPCs are more prevalent in PBC patients than in controls and are strongly associated with more active and severe disease.

Autoantibodies↗

PubMed2003

Improvement of prognostic power of the Child-Pugh classification of liver cirrhosis by hyaluronan.

BACKGROUND/AIMS: Modifications of the Child-Pugh classification of liver cirrhosis by incorporation of hyaluronan were tested to improve the prognostic power for long term evaluation of liver cirrhosis in 126 patients observed over a period of 10 years. METHODS: Serum concentrations of HA were determined at study entry. Statistical analysis included Kaplan-Meier life tables and stepwise multivariant Cox-regression analysis for each parameter of Child-Pugh classification and hyaluronan. Prognostic models were developed by exchanging prothrombin time, albumin and encephalopathy by HA in different combinations. RESULTS: Based on a good single correlation between hyaluronan (0.62) and clinical course (P<0.01) we conclude that models with hyaluronan instead of albumin or encephalopathy and with or without shifted threshold values of bilirubin and albumin are superior for the prediction of the long term prognosis. In Cox-regression analysis, apart from hyaluronan and bilirubin, no other parameters contributed to an improvement. CONCLUSIONS: We conclude that a modification of the Child-Pugh classification of liver cirrhosis by inclusion of HA significantly improves the predictive power of CP, especially in alcoholic etiology. A prospective validation of the newly defined scores needs to be done in the future.

Adult↗

PubMed1997

Early indicators of prognosis in fulminant hepatic failure: an assessment of the King's criteria.

BACKGROUND/AIMS: An accurate and early assessment of the individual patient is critical in deciding whether liver transplantation is indicated in the treatment of fulminant hepatic failure. Based on analysis of patients treated between 1973 and 1985, the Liver Unit at King's College Hospital, London, developed a prognostic model to identify patients with a poor prognosis. The present study was done to determine the applicability of this model in fulminant hepatic failure patients seen at our center in the 1990s. METHODS: The records of 145 patients with fulminant hepatic failure, treated conservatively at Queen Elizabeth Hospital, Birmingham between 1990 and 1994, were analyzed. An additional 81 patients, who were transplanted for fulminant hepatic failure during the same period were excluded from the study. RESULTS: Application of King's College Hospital criteria at the time of admission to this hospital in the acetaminophen group, had a positive predictive value of 88%, negative predictive value of 65% and predictive accuracy of 71%. The positive predictive value, negative predictive value and predictive accuracy of these criteria for non-acetaminophen-induced fulminant hepatic failure, were 79%, 50% and 68%. Multivariate analysis identified prothrombin time, serum creatinine, white cell count and abnormal potassium levels as independent predictors of mortality in acetaminophen-induced fulminant hepatic failure; and prothrombin time alone in fulminant hepatic failure induced by other etiologies. CONCLUSIONS: The King's College Hospital criteria for predicting outcome of fulminant hepatic failure were found to have a slightly lower predictive accuracy than shown in the original study.

Acetaminophen↗

PubMed2000

Predictors of poor outcome in chronic dialysis patients: The Netherlands Cooperative Study on the Adequacy of Dialysis. The NECOSAD Study Group.

In a prospective cohort study, we constructed a composite index of poor outcome that incorporates survival, morbidity, and quality of life (QL). We identified baseline patient and treatment characteristics that predicted poor outcome 1 year after the start of chronic dialysis. Outcome was classified as poor if a patient had died or if at least two of the following criteria were present: (1) 30 days or greater of hospitalization per year, (2) serum albumin level of 30 g/L or less or a malnutrition index score of 11 or greater, (3) a 36-item Medical Outcomes Study (MOS)-Short Form Health Survey Questionnaire (SF-36) physical summary QL score of 2 or more SDs less than the general population mean score, and (4) an SF-36 mental summary QL score of 2 or more SDs less than the general population mean score. Multivariate logistic regression analysis was used to identify independent predictors of poor outcome. Of 250 included patients, 189 were assessable with respect to poor outcome. Of these patients, 47 (25%) were classified as poor. A baseline presence of comorbidity, serum albumin level of 30 g/L or less, physical or mental QL score 2 or more SDs less than the general population mean score, and, to a lesser extent, residual glomerular filtration rate of 2.5 mL/min/1.73 m(2) or less were independently associated with a greater risk for poor outcome. A post hoc analysis indicated a mean arterial blood pressure greater than 107 mm Hg was predictive of poor outcome in patients undergoing peritoneal dialysis. In conclusion, our prognostic model provides a useful tool to identify chronic dialysis patients at risk for poor health status. Strategies aimed at preserving residual renal function, controlling blood pressure, monitoring QL, and consequently giving psychosocial support may reduce the risk for poor outcome.

Adult↗

PubMedDate not supplied

[What is the cost of inappropriate admission of pneumonia patients?].

BACKGROUND: The number of patients admitted with community-acquired pneumonia (CAP) varies greatly from one hospital to another. Prognostic models for CAP can help physicians decide which cases to treat on an outpatient basis. Our aims were: a) to validate a model for predicting low-risk CAP, and b) to estimate savings that would have resulted if the low-risk patients identified by the model had been treated at home rather than in hospital. PATIENTS AND METHODS: All CAP cases diagnosed by the emergency room physicians of a hospital in northwestern Spain (Ferrol) were enrolled prospectively over a period of 19 months. The prediction rule of Fine et al was used to classify all patients. Mortality in each category was compared with the mortality predicted by Fine's system. Patients in the lowest risk categories (I and II) were considered to have been inappropriately admitted unless they were hypoxemic or had significant comorbidity. Costs were figured based on data provided by our accounting department. RESULTS: Of 192 CAP patients enrolled, 131 were admitted and 61 were treated as outpatients. Ten patients died, none of whom was in classes I or II. The costs of the apparently unnecessary hospital stays of the 34 patients in these classes was 6,979,756 pesetas. The estimated savings that would have derived from treating these patients out-of-hospital was 6,133,292 pesetas (36,862 euros; 322,804 pesetas/month). CONCLUSIONS: a) The predictive model used has been found useful for identifying patients at very low risk of dying from CAP; b) Using this model can improve CAP admission criteria, and c) Application of the model can lead to savings.

Community-Acquired Infections↗

PubMed1986

Extent and severity of myocardial hypoperfusion as predictors of prognosis in patients with suspected coronary artery disease.

The ability of exercise-induced myocardial hypoperfusion on thallium scintigraphy to predict coronary events was assessed in 1,689 patients with symptoms suggestive of coronary artery disease but without prior myocardial infarction or coronary artery bypass surgery. A total of 74 patients had a coronary event in the year after testing (12 cardiac deaths, 20 nonfatal infarctions and 42 referrals for bypass surgery more than 60 days after testing). Stepwise logistic regression identified only three independent predictors: the number of myocardial regions with reversible hypoperfusion (an index of the extent of hypoperfusion), the maximal magnitude of hypoperfusion (an index of the severity of hypoperfusion) and the achieved heart rate (an index of exercise performance). Both extent and severity were exponentially correlated with event rate (r greater than 0.97 and p less than 0.01 for each), whereas achieved heart rate was linearly correlated with event rate (r = 0.79 and p less than 0.05). On the basis of these data, a prognostic model was defined that employs extent and severity as stress-dependent orthogonal variables. Using this model, the predicted coronary event rate ranged over two orders of magnitude--from a low of 0.4% in patients able to exercise adequately without developing severe and extensive hypoperfusion at a low heart rate (less than 85% of their maximal predicted heart rate). Extent and severity of myocardial hypoperfusion, therefore, are important independent variables of prognosis in patients with suspected coronary artery disease.

Aged↗