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D L Patrick

Publications and source records attributed to D L Patrick.

At least 73 records · Page 4Linked to original sources
PubMed1997

Effect size and power for clinical trials that measure years of healthy life.

Some clinical trials perform repeated measurements on patients over time, plot those measures against time, and summarize the results in terms of the area under the curve. If the measured variable is health status, the summary outcome is sometimes referred to as years of healthy life (YHL), or quality-adjusted life years (QALY). This paper investigates some theoretical and practical aspects of randomized trials designed to assess measures such as YHL. We first derived algebraic expressions for the effect size of YHL measures under several theoretical models of the treatment's effect on health. We used these expressions to examine how the length of the study, the number of measurements per person and the correlations among health measurements over time influence the effect size. We also explored the relative statistical power of analyses based on YHL versus analyses based on change-scores using the same data. We present an example. Findings suggest that: (i) the number of measurements per person need not be large; (ii) high correlation among measures over time tends to lower the power of a study using YHL; (iii) a longer study will not always provide more power than a shorter study, and (iv) analyses based on YHL may have less power than change-score analyses. Some of these findings depend on the model of change in health status caused by the treatment. Such models require further study.

Effect Modifier, Epidemiologic↗
PubMed1997

Depressive symptoms and the cost of health services in HMO patients aged 65 years and older. A 4-year prospective study.

OBJECTIVE: To examine whether depressive symptoms in older adults contribute to increased cost of general medical services. DESIGN: A 4-year prospective cohort study. SETTING: Four primary care clinics of a large staff-model health maintenance organization (HMO) in Seattle, Wash. PATIENTS: A total of 5012 Medicare enrollees older than 65 years were invited to participate in the study; 2558 subjects (51%) were successfully enrolled. Non-participants were somewhat older and had a higher level of chronic medical illness. MAIN OUTCOME MEASURES: Depressive symptoms as measured by the Center for Epidemiological Studies Depression scale, which was administered as part of a mail survey at baseline, at 2 years, and at 4 years; and total cost of medical services from the perspective of the HMO. Data were obtained from the cost accounting system of the HMO. RESULTS: In this cohort of older adults, depressive symptoms were common, persistent, and associated with a significant increase in the cost of general medical services. This increase was seen for every component of health care costs and was not accounted for by an increase in specialty mental health care. The increase in health care costs remained significant after adjusting for differences in age, sex, and chronic medical illness. CONCLUSIONS: Depressive symptoms in older adults are associated with a significant increase in the cost of medical services, even after adjusting for the severity of chronic medical illness.

Aged↗
PubMed1997

Hostility, aggression and the risk of nonfatal myocardial infarction in postmenopausal women.

Hostility can predict coronary heart disease (CHD) and total mortality in men. However, in women this association has not been as thoroughly explored. This study examines whether hostile and aggressive attitudes are associated with myocardial infarction (MI) in postmenopausal women. Cases included 277 women who presented with an incident MI. Controls included a random sample of 988 female health maintenance organization enrollees. Women were asked the Hostile-Affect and the Aggressive-Responding factors of the Cook-Medley Hostility Scale. The Hostile-Affect score was linearly associated with increased risk for MI (odds ratio [OR] per point = 1.22; 95% confidence interval [CI95%] = 1.07-1.38), whereas the Aggressive-Responding score had a modest protective effect (OR = 0.92 per point; CI95% = 0.84-1.02); p = 0.009. Adjustment for sociodemographic and MI risk factors altered these results only slightly. These hostility measures are easily administered, and could help to identify women who are at high risk for CHD and who may benefit from preventive measures.

Adult↗
PubMed1997

Willingness to pay for antihypertensive care: evidence from a staff-model HMO.

Willingness to pay (WTP) has been used in Sweden to evaluate the value of antihypertensive therapy. The Swedish studies indicate that hypertensive patients are willing to pay between $107 and $120 per month for their therapy. We conducted a similar study in a population of hypertensive patients in a large, staff-model, managed care organization (Group Health Cooperative of Puget Sound). Participants returned a postal survey containing a WTP question with 10 "bids" ranging from $25 to $250. Respondents recorded whether they would accept or reject each bid at the stated dollar value. Demographic information such as age, income, and perceived health status was also collected. Results were analyzed with ordinary least squares regression, controlling for the demographic data. The estimated parameters were significant and indicated an adjusted mean WTP of $93 per month for antihypertensive therapy. The close similarity of the Swedish and U.S. results appears to support the use of WTP as a measure of health state preferences.

Age Factors↗
PubMed1997

Assessing health-related quality-of-life and health state preference in persons with obesity: a validation study.

The objective of this study was to assess the reliability, validity and responsiveness of a new health-related quality-of-life (HRQOL) measure containing global and obesity-specific domains and an obesity-specific health state preference (HSP) assessment. A total of 417 obese and 'normal' weight individuals completed these assessments. Internal consistency and test-retest reliability were demonstrated, with Cronbach's alpha, intraclass correlation coefficient and kappa values well above the acceptable level for most scales. Construct validity hypotheses were confirmed by examining scale correlations. The normal weight individuals reported statistically significantly better functioning and well-being on the majority of the HRQOL scales and HSP than obese individuals. Guyatt's statistic of responsiveness was moderate to high for all the scales and items in the weight-loss and weight-gain groups; however, many of the scales and items in the weight-stable group also displayed responsiveness. The results of this study support the reliability and validity of these assessments. However, further testing is needed to evaluate the responsiveness of both assessments in a weight-stable group.

Adult↗
PubMed1997

Barriers to communication about end-of-life care in AIDS patients.

OBJECTIVE: Patients and physicians do not adequately discuss patients' preferences for medical care at the end of life. Our objective was to perform a qualitative study using focus groups to identify barriers and facilitators to communication about end-of-life medical care for patients with AIDS and their physicians. PARTICIPANTS: Patients with AIDS and physicians with moderate or extensive HIV experience were recruited from clinics and community-based settings using network sampling. A total of 47 patients participated in six focus groups and 19 physicians participated in three groups. MEASUREMENTS AND MAIN RESULTS: Patients or physicians identified 29 barriers and facilitators to communication about end-of-life care. Many patients and physicians expressed discomfort talking about death and dying, and some felt that discussing end-of-life care could cause harm or even hasten death. Several patients expressed the view that a living will obviated the need for discussion with their physician. Previous experience of discrimination from the health care system was a strong barrier to end-of-life communication for some patients with AIDS. Some patients hesitate to bring up end-of-life issues because they want to protect their physicians from uncomfortable discussions. Many patients identified the quality of communication as an important facilitator to these difficult discussions. CONCLUSIONS: Improving the quality of patient-physician communication about end-of-life care will require that physicians identify and overcome the barriers to this communication. To improve the quality of medical care at the end of life, we must address the quality of communication about end-of-life care.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Finding health-related quality of life outcomes sensitive to health-care organization and delivery.

OBJECTIVES: The author identifies and assesses health-related quality-of-life outcomes for evaluating health-care structure and process. METHODS: Development of a conceptual model and presentation of case studies are used to identify methods of outcomes research necessary to evaluate health-care organization and delivery. RESULTS: Generic measures already exist for assessing functional status and well-being outcomes of health care. Condition-specific measures are necessary to address directly the concerns of patients and providers of care and to detect small differences in organizational arrangements. Improved health outcomes are more likely to be observed from large-scale prospective trials and studies using large data sets, but few studies report improved self-reported health status as linked to organizational structure. CONCLUSIONS: Theoretically driven research is necessary to link healthcare systems and outcomes. Outcome measures exist, but measurement development is needed for organizational arrangements, managed care structure and process, and stakeholder exchanges.

Delivery of Health Care↗
PubMed1997

Relative importance of sexuality and quality of life in patients with prostatic symptoms. Results of an international study.

OBJECTIVE: Benign prostatic hyperplasia (BPH) and its treatment can impair the quality of life (QoL) of patients with the condition. Among the BPH-specific instruments available for assessing QoL, no consensus has emerged on the concepts that should be measured, particularly for aspects of sexual life. The objective of this study was to determine which aspects of QoL were most affected by prostatic symptoms and which patients considered the most important. METHOD: After an extensive literature review, we drew up a self-administered questionnaire composed of an exhaustive list of concepts found in the available QoL/BPH measures. In a cross-sectional study, 73 French and 44 English patients with an International Prostate Score (I-PSS) > 7 were asked to fill in this 89-item questionnaire. The level of interference of the symptoms with each aspect of QoL and the importance of the problem were reported by the patients. RESULTS: The aspects reported to be most affected and to be the most important were sleep, anxiety and worry about the disease, mobility, leisure, daily activities, sexual activities and satisfaction with sexual relationships. French patients considered all sexual aspects of life more important than English patients. CONCLUSION: This study confirms that QoL is an important outcome in BPH. The major concepts identified by the patients to be important include sexual ones. These results suggest the importance of including the assessment of sexual functioning and behavior in any further evaluations of BPH treatments effects on QoL.

Aged↗
PubMed1997

Use of the Health Utilities Index with stroke patients and their caregivers.

BACKGROUND AND PURPOSE: Few studies currently assess the health-related quality of life of individuals following a stroke. One of the major challenges of assessing quality of life is the high likelihood that after a stroke a patient will not be able to complete such an assessment. One practical solution is to have a family caregiver complete the assessment on behalf of these individuals. This current pilot study examined the interrater reliability of having family caregivers complete the Health Utilities Index (HUI) on behalf of stroke patients. METHODS: A total of 74 patients who experienced an ischemic stroke and 37 family caregivers completed the interviewer-administered HUI (data were available for 33 pairs). The HUI is designed to produce a single summary measure of health-related quality of life, the global multiattribute utility score, as well as descriptive information on each of its attributes. Interrater reliability was measured by evaluating the percent agreement, Cohen's kappa statistics, intraclass correlation coefficients (ICCs), Pearson's R correlations, and paired t tests between the patient and caregiver responses. RESULTS: In most instances interrater reliability was acceptable, with values suggesting moderate to high agreement. The mean global multiattribute utility scores for the HUI 2 were identical for patients and caregivers (0.64 +/- 0.29), with an ICC of .72. A preponderance of patients reported decrements in several attributes of the HUI. CONCLUSIONS: These data indicate a substantial decrement in functioning in stroke patients and suggest that family caregivers can complete the HUI reliably when patients are unable to do so.

Adult↗
PubMed1997

Issues in the measurement of satisfaction with treatment.

Patients satisfaction with treatments is a growing area of research that has tremendous potential to provide outcome measures for clinical trials and disease management programs. It also has applications in marketing and product development, especially for the treatment of chronic diseases. The objective of this review is to demonstrate that treatment satisfaction is a distinct area of research that has produced some important initial results. We define treatment satisfaction and provide a conceptual framework that clarifies the role of treatment expectations, preferences, and satisfaction in the context of healthcare in general. Nineteen articles were selected from more than 1,400 abstracts and were reviewed for the following information: (1) topics covered; (2) method used to design the measure; (3) descriptive statistics; (4) assessment with respect to the attributes in the Instrument Review Criteria of the Medical Outcome Trust's Scientific Advisory Committee; and (5) covariates. We conclude that some important initial results about treatment satisfaction have been obtained, but that much work remains to be performed. We recommend that future research devote more attention to qualitative research with patients, assessment of the measures, and the covariates presented in the conceptual model. We also recommend that decision makers insist on measures that meet these criteria.

Chronic Disease↗
PubMed1997

Health care utilization for the "newly insured": results from the Washington Basic Health Plan.

The risk of providing coverage for low-income people formerly without insurance is unknown. We conducted an evaluation to describe the use of services from 1989-1992 for members of the Basic Health Plan (BHP), a subsidized health insurance program for low-income individuals in the state of Washington. There was evidence of pent-up demand for care for those who had been without insurance for more than a year. Overall, members in the BHP program were not high users of care, although one of the three plans we examined had significantly higher utilization than the other two. BHP total expenditures were comparable to those for state employees and lower than those for Medicaid recipients.

Adolescent↗
PubMed1996

The Quebec Task Force classification for Spinal Disorders and the severity, treatment, and outcomes of sciatica and lumbar spinal stenosis.

STUDY DESIGN: A prospective cohort study of patients in Maine with sciatica and lumbar spinal stenosis treated surgically and nonsurgically. SUMMARY OF BACKGROUND DATA: In 1987, the Quebec Task Force on Spinal Disorders proposed a diagnostic classification to help make clinical decisions, evaluate quality of care, assess prognosis, and conduct research. OBJECTIVES: To assess the Quebec Task Force classification's ability to stratify patients according to severity and treatment at baseline, and to assess changes over time in health-related quality of life, including symptoms, functional status, and disability. METHODS: Five hundred sixteen patients participating in the Maine Lumbar Spine Study who completed baseline and 1-year follow-up evaluations were classified successfully according to the Quebec Task Force classification. Patient characteristics and treatments were compared across Quebec Task Force classification categories. Changes in health-related quality of life over 1 year were assessed according to Quebec Task Force classification category and type of treatment. RESULTS: Among patients with sciatica (n = 370), higher Quebec Task Force classification categories (from 2, pain radiating to the proximal extremity, to 6, sciatica with evidence of nerve root compression) were associated with increased severity of symptoms at baseline. There was no association between Quebec Task Force classification and baseline functional status. Quebec Task Force classification was associated strongly with the likelihood of receiving surgical treatment (P < or = 0.005). Among patients with sciatica treated nonsurgically, improvement at 1 year in back-specific and generic physical function increased with higher Quebec Task Force classification category (P < or = 0.05). Only a nonsignificant trend was observed for surgically treated patients. Patients with lumbar spinal stenosis (Quebec Task Force classification 7, n = 131) had baseline features and outcomes distinct from patients with sciatica. CONCLUSIONS: For patients with sciatica, the Quebec Task Force classification was highly associated with the severity of symptoms and the probability of subsequent surgical treatment. Nonsurgically treated patients in Quebec Task Force classification categories reflecting nerve root compression had greater improvement than those with pain symptoms alone. Among surgical patients, the Quebec Task Force classification was not associated with outcome. These results provide validation for the classification and its wider adoption. Nonetheless, improved diagnostic classifications are needed to predict outcomes better in patients with sciatica who undergo surgery.

Adolescent↗
PubMed1996

The Maine Lumbar Spine Study, Part I. Background and concepts.

STUDY DESIGN: This paper describes the background and factors that led to the development and implementation of the Maine Lumbar Spine Study, a prospective cohort study of patients undergoing surgical and nonsurgical treatment of herniated lumbar disc with sciatica and symptomatic spinal stenosis. OBJECTIVES: To define the factors leading to the study and the methods of designing and implementing a community-based effectiveness study to evaluate the outcomes of herniated lumbar intervertebral disc and spinal stenosis. SUMMARY OF BACKGROUND DATA: Variations in the utilization of surgery for these conditions and physicians' uncertainty regarding the best way to manage them resulted in support of a community-based study of the effectiveness of treatment alternatives. METHODS: A prospective cohort design was used. Methods of patient enrollment, data collection, management, and analysis are described. An innovative method of ascertaining the representativeness of the enrolled versus nonenrolled patient population is presented. RESULTS: The importance of developing community-based networks of physicians is discussed. CONCLUSIONS: These networks play an important role in analyzing practice pattern variations and in stimulating and participating in effectiveness research. Because effectiveness studies must be conducted at the community level, mechanisms must be developed with which to support and implement these efforts.

Cohort Studies↗
PubMed1996

The Maine Lumbar Spine Study, Part II. 1-year outcomes of surgical and nonsurgical management of sciatica.

STUDY DESIGN: The Maine Lumbar Spine Study is a prospective cohort study of patients recruited from the practices of orthopedic surgeons, neurosurgeons, and occupational medicine physicians throughout Maine. OBJECTIVE: To assess 1-year outcomes of patients with sciatica believed to be due to a herniated lumbar disc treated surgically or nonsurgically. SUMMARY OF BACKGROUND DATA: Lumbar spine surgery rates vary by geographic region and may reflect uncertainty about optimal clinical use. METHODS: Eligible consenting patients participated in a baseline interview performed by study personnel and then were mailed follow-up questionnaires at 3, 6, and 12 months. Clinical data were obtained from a physician questionnaire. Outcomes included patient-reported symptoms of leg and back pain, functional status, disability, quality of life, and satisfaction with care. RESULTS: Five hundred seven patients with sciatica, 275 treated surgically and 232 treated nonsurgically initially, were enrolled. Surgically treated patients, on average, had more severe symptoms and had more severe physical and imaging findings than nonsurgically treated patients at entry. Although few surgically treated patients had mild symptoms and few nonsurgically treated patients had severe symptoms, about half in each treatment group had symptoms that fell into a moderate category. At the 1-year evaluation, improvement in symptoms, functional status, and disability were found in both treatment groups. However, surgically treated patients reported significantly greater improvement. For the predominant symptom, either back or leg pain, 71% of surgically treated and 43% of nonsurgically treated patients reported definite improvement (P < 0.001). This effect was even greater after adjustment for differences between treatment groups at entry (relative odds of definite improvement, 4.3; P < 0.001). For patients with moderate symptoms and abnormal physical examination findings, surgical treatment also resulted in greater improvement than nonsurgical treatment. However, there was little difference in the employment or workers' compensation status of patients treated surgically versus nonsurgically (5% vs. 7% unemployed at 1-year follow-up if employed at entry [P = 0.68]; 46% vs. 55% receiving workers' compensation at 1-year follow-up if receiving it at entry [P = 0.30] for surgical and nonsurgical management, respectively). For patients with mild symptoms, the benefits of surgical and nonsurgical treatment were similar. CONCLUSIONS: Although surgically treated patients were on average more symptomatic at entry, there was substantial overlap in symptoms between surgically treated and nonsurgically treated patients. Surgically treated patients with sciatica reported substantially greater improvement at 1-year follow-up. However, employment and compensation outcomes were similar between the two treatment groups, and surgery appeared to provide little advantage for the subset of patients with mild symptoms. These results should be interpreted cautiously, because surgical treatment was not assigned randomly. Long-term follow-up will determine if these differences persist.

Adolescent↗
PubMed1996

The Maine Lumbar Spine Study, Part III. 1-year outcomes of surgical and nonsurgical management of lumbar spinal stenosis.

STUDY DESIGN: A prospective cohort study of patients with lumbar spinal stenosis recruited from the practices of orthopedic surgeons and neurosurgeons throughout Maine. OBJECTIVE: To assess 1-year outcomes of patients with lumbar spinal stenosis treated surgically or nonsurgically. SUMMARY OF BACKGROUND DATA: No randomized trials and few nonexperimental studies have compared surgical and nonsurgical treatment of patients with lumbar spinal stenosis. The authors' goal was to assess 1-year outcomes of patients with lumbar spinal stenosis treated surgically or nonsurgically. METHODS: Eligible, consenting patients participated in baseline interviews and were then mailed follow-up questionnaires at 3, 6, and 12 months. Clinical data were obtained from a physician questionnaire. Outcomes included patient-reported symptoms of leg and back pain, functional status, disability, and satisfaction with care. RESULTS: One hundred forty-eight patients with lumbar spinal stenosis were enrolled, of whom 81 were treated surgically and 67 treated nonsurgically. On average, patients in the surgical group had more severe imaging findings and symptoms and worse functional status than patients in the nonsurgical group at entry. Few patients with mild symptoms were treated surgically, and few patients with severe symptoms were treated nonsurgically. However, of the patients with moderate symptoms, a similar percent were treated surgically or nonsurgically. One year after study entry, 28% of nonsurgically and 55% of surgically treated patients reported definite improvement in their predominant symptoms (P = 0.003). For patients with moderate symptoms, outcomes for surgically treated patients were also improved compared with those of nonsurgically treated patients. Surgical treatment remained a significant determinant of 1-year outcome, even after adjustment for differences between treatment groups at entry (P = 0.05). The maximal benefit of surgery was observed by the time of the first follow-up evaluation, which was at 3 months. Although few nonsurgically treated patients experienced a worsening of their condition, there was little improvement in symptoms and functional status compared with study entry. CONCLUSIONS: At a 1-year evaluation of patient-reported outcomes, patients with severe lumbar spinal stenosis who were treated surgically had greater improvement than patients treated nonsurgically. Comparisons of outcomes by treatment received must be made cautiously because of differences in baseline characteristics. A determination of whether the outcomes observed persist requires long-term follow-up.

Adult↗