Standardizing primary care physician panels: is age and sex good enough?

OBJECTIVES: To determine if patient clinical conditions need to be considered when assessing primary care physician (PCP) workload in the context of standardizing panel sizes. STUDY
DESIGN: Work resource value units (wRVUs) were used to standardize PCP panel workload. Standardized panels were created using (1) age and sex- and (2) clinical condition-based risk indicators. Billing data were used for all patients, regardless of insurance, for PCPs in a group practice (n = 190). Weighting methods were assessed for subgroups based on PCP specialty (family medicine, internal medicine, and pediatrics) and patient age (adults vs children) and for different levels of aggregation (patient vs PCP).
METHODS: Groupwide weights based on wRVUs of all primary care services delivered during the year were applied to individual patients and then aggregated to PCP panels. For age/sex weighting, only patient age and sex were taken into account. For condition-based weighting, 1275 disease categories, based on a combination of episode treatment groups (ETGs) and age and/or sex, were used.
RESULTS: As expected, at the patient level, condition-based weights were far more discriminative than age/sex. At the PCP level, this discrimination was less important; panel weights varied 1.9- (age/sex-based) to 2.6-fold (condition-based) across PCPs. Correlations between the 2 weighting methods were high (r = 0.93) for child panels and moderate (r = 0.71) for adult panels (all P <.001).
CONCLUSIONS: The heterogeneity of PCP panels should be considered when assessing PCP workload for panel management. Panel variability in workload is well captured by age/sex-based weights for children, but for adults condition-based adjustment may be necessary.