Search PubMedSearch

PubMed · 8800607

A SAS macro for stepwise correlated binary regression.

Abstract

Several regression methods have been proposed for the analysis of correlated binary data, but none deals with the selection of covariates when there exist a large number of potentially relevant covariates. We present a SAS macro based on a stepwise selection procedure for the analysis of correlated binary data. Using regression methods based on generalized estimating equations originally proposed by Liang and Zeger and extended by Prentice, we describe a score test for forward selection, a Wald's test for backward elimination, and a test for model adequacy based on generalized scores. The methodology and the accompanying computer macro program written in SAS IML are illustrated with data from a prospective study of functional decline in the activities of daily living in a group of elderly patients.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

I F Nuamah, Y Qu, S B Amini. 1996. A SAS macro for stepwise correlated binary regression.. https://doi.org/10.1016/0169-2607(96)01718-x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Systematic review of the effectiveness of planned short hospital stays for mental health care.

OBJECTIVE: To determine the effectiveness of planned short hospital stays versus standard care for people with serious mental illness. DESIGN: Systematic review of all randomised controlled trials comparing planned short hospital stay versus long hospital stay or standard care for people with serious mental illness. SUBJECTS: Four trials enrolled 628 patients. MAIN OUTCOMES MEASURES: Relapse; readmission; death (suicides and all causes); violent incidents (self, others, property); lost to follow up; premature discharge; delayed discharge; mental state (not improved); social functioning; patient satisfaction, quality of life, self esteem, and psychological wellbeing; family burden; imprisonment; employment status; independent living; total cost of care; and average length of hospital stay. RESULTS: Patients allocated to planned short hospital stays had no more readmissions (in four trials, odds ratio 0.93, 95% confidence interval 0.66 to 1.29 with no heterogeneity between trials), no more losses to follow up (in three trials of 404 patients, 1.09, 0.62 to 1.91 with no heterogeneity between trials), and more successful discharges on time (in three trials of 404 patients, 0.47, 0.27 to 0.85) than patients allocated long hospital stays or standard care. Some evidence showed that patients allocated planned short hospital stay were no more likely to leave hospital prematurely and had a greater chance of being employed than those allocated long hospital stay or standard care. Data on mental, social, and family outcomes could not be summated, and there were few or no data on patient satisfaction, deaths, violence, criminal behaviour, and costs. CONCLUSION: The effectiveness of care in mental hospitals is important to patients, carers, and policy makers. Despite inadequacies in the data, this review suggests that planned short hospital stays do not encourage a "revolving door" pattern of care for people with serious mental illness and may be more effective than standard care. Further pragmatic trials are needed on the most effective organisation and delivery of care in mental hospitals.

Activities of Daily Living

Concomitant chemoradiotherapy for patients with nonmetastatic breast carcinoma: side effects, quality of life, and organization.

BACKGROUND: This study was designed to investigate the personal experience of patients with nonmetastatic breast carcinoma who were treated with the concurrent administration of radiotherapy and chemotherapy in terms of side effects and quality of life (QL). METHODS: One hundred nine patients with nonmetastatic breast carcinoma, recruited between May 1995 and February 1997, were included in a protocol combining chemotherapy with mitoxantrone and cyclophosphamide, administered intravenously in 4 cycles of 21 days, and concomitant radiotherapy. Side effects of treatment and its impact on patients' daily lives were measured using ad hoc questionnaires; QL was measured by the European Organization for Research and Treatment of Cancer QLQ-C30 QL questionnaire, and pain was measured by a visual analogue scale (VAS). RESULTS: All patients agreed to participate. The mean number of chemotherapy and radiotherapy symptoms per cycle were: 7.2+/-2.5 and 2.4+/-1.8, respectively. Chemotherapy symptoms generally were more frequent and distressing than those of radiotherapy. The average pain score reported on the VAS by patients during treatment was 3.0+/-2.0. Multidimensional QL assessment showed that treatment mainly affects physical functioning and global QL. Multivariate analysis showed that the main determinants of QL at the end of treatment were fatigue, pain, and loss of appetite experienced during treatment. Moreover, 62.8% of patients required specific help for transportation to the hospital and/or home upkeep. CONCLUSIONS: The concurrent administration of chemotherapy and radiotherapy deteriorates patients' QL but in a proportion similar to sequential administration while presenting the advantage of a shorter duration of treatment. However, increased fatigue, pain, and loss of appetite as well as difficulties in patients' daily lives have to be taken into account in therapeutic decision-making analysis.

Activities of Daily Living

Changes in resource use and outcomes for patients with migraine treated with sumatriptan: a managed care perspective.

BACKGROUND: Migraine headaches result in significant patient suffering and high costs to managed care organizations and employers. Studies that evaluate patient outcomes and the financial consequences of migraine treatment are important from a clinical and an economic perspective. METHODS: This prospective, observational study assessed the outcomes of migraineurs in a mixed model staff/ independent practice association managed care organization for patients previously diagnosed as having migraine who received their first prescription for sumatriptan. Data collected included medical as well as pharmacy claims and patient surveys to measure changes in satisfaction, health-related quality of life, workplace productivity, and nonworkplace activity after sumatriptan therapy was initiated. RESULTS: A total of 178 patients completed the study. Results showed significant decreases in the mean number of migraine-related physician office visits, emergency department visits, and medical procedures in the 6 months after sumatriptan therapy compared with the 6 months before sumatriptan was used (P<.05). Four of the health-related quality-of-life dimensions and the physical component summary score measured by the SF-36 (which is a valid, reliable general health status instrument) showed significant improvements at 6 months compared with patients' scores before use of sumatriptan (P<.05). Health-related quality of life measured by the disease-specific instrument MSQ (Migraine-Specific Quality of Life Questionnaire-Version 1.0, 1992 Glaxo Wellcome Inc, Research Triangle Park, NC) showed significant improvement at 3 and at 6 months compared with baseline scores (P<.05). There were also improvements in patient satisfaction and significant reductions in time lost from workplace productivity and nonworkplace activity. CONCLUSION: In the 6 months after sumatriptan therapy was initiated, health care resource use and time lost from workplace productivity and nonworkplace activity were reduced, while health-related quality of life and patient satisfaction scores improved for the managed care migraineurs enrolled in this study.

Activities of Daily Living