Who can respond to treatment? Identifying patient characteristics related to heterogeneity of treatment effects

Med Care. 2010 Jun;48(6 Suppl):S9-16. doi: 10.1097/MLR.0b013e3181d99161.

Abstract

Background: Interest in comparative effectiveness research and the rising number of negative or "small effect" trials have stimulated research into differential response to treatment among subgroups of patients.

Objective: To develop and test the Potential for Benefit Scale (PBS), a composite measure to identify subgroups of patients with differential potential for response to treatment, using diabetes as a model.

Design: Cross-sectional and longitudinal cohort study.

Subjects and setting: Type 2 diabetes patients (n = 1361) were identified from 7 outpatient clinics serving a diverse population. Of these, 611 completed a 1-year follow-up.

Measures: To represent patients' health status, we used the Total Illness Burden Index, the Physical Function Index of the SF-36, the Center for Epidemiologic Studies Depression Scale, and the Diabetes Burden Scale. To represent personality characteristics related to health, we used the Provider-Dependent Health Care Orientation scale. We assessed the contribution of these measures to a composite scale of patients' potential for treatment response in terms of self-reported medication adherence and glycemic control.

Results: Principal components analysis confirmed associations among these measures. The internal consistency reliability of the PBS was adequate (Cronbach alpha = 0.65). Patients in the lowest versus highest quartile of the PBS reported poorer adherence (18% vs. 55%, P < 0.001) and poorer glycemic control at baseline (mean hemoglobin A1c values: 7.75 vs. 7.39, P < 0.001). Those in the highest quartile of the PBS also were more likely to reach target values for glycemic control (HbA1c <7%) at 1-year follow-up, (adjusted OR = 1.61, P < 0.05).

Conclusions: The PBS, a composite scale, may be helpful in identifying patients with differential potential for response to treatment.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Aged
  • Blood Glucose
  • Child
  • Comorbidity
  • Comparative Effectiveness Research / organization & administration*
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / psychology*
  • Diabetes Mellitus, Type 2 / therapy*
  • Female
  • Follow-Up Studies
  • Glycated Hemoglobin A
  • Humans
  • Medication Adherence*
  • Middle Aged
  • Personality
  • Severity of Illness Index
  • Sex Factors
  • Socioeconomic Factors

Substances

  • Blood Glucose
  • Glycated Hemoglobin A