The Doctors’ Effect on Patients’ Physical Health Outcomes Beyond the Intervention: A Methodological Review

BACKGROUND: Previous research suggests that when a treatment is delivered, patients’ outcomes may vary systematically by medical practitioner. OBJECTIVE: To conduct a methodological review of studies reporting on the effect of doctors on patients’ physical health outcomes and to provide recommendations on how this effect could be measured and reported in a consistent and appropriate way. METHODS: The data source was 79 included studies and randomized controlled trials from a systematic review of doctors’ effects on patients’ physical health. We qualitatively assessed the studies and summarized how the doctors’ effect was measured and reported. RESULTS: The doctors’ effects on patients’ physical health outcomes were reported as fixed effects, identifying high and low outliers, or random effects, which estimate the variation in patient health outcomes due to the doctor after accounting for all available variables via the intra-class correlation coefficient. Multivariable multilevel regression is commonly used to adjust for patient risk, doctor experience and other demographics, and also to account for the clustering effect of hospitals in estimating both fixed and random effects. CONCLUSION: This methodological review identified inconsistencies in how the doctor’s effect on patients’ physical health outcomes is measured and reported. For grading doctors from worst to best performances and estimating random effects, specific recommendations are given along with the specific data points to report.