Provider practice characteristics that promote interpersonal continuity.

PURPOSE Becoming certified as a patient-centered medical home now requires practices to measure how effectively they provide continuity of care. To understand how continuity can be improved, we studied the association between provider practice characteristics and interpersonal continuity using the Usual Provider Continuity Index (UPC). METHODS We conducted a mixed-methods study of the relationship between provider practice characteristics and UPC in 4 university-based family medicine clinics. For the quantitative part of the study, we analyzed data extracted from monthly provider performance reports for 63 primary care providers (PCPs) between July 2009 and June 2010. We tested the association of 5 practice parameters on UPC: (1) clinic frequency; (2) panel size; (3) patient load (ratio of panel size to clinic frequency); (4) attendance ratio; and (5) duration in practice (number of years working in the current practice). Clinic, care team, provider sex, and provider type (physicians versus nonphysician providers) were analyzed as covariates. Simple and multiple linear regressions were used for statistical modeling. Findings from the quantitative part of the study were validated using qualitative data from provider focus groups that were analyzed using sequential thematic coding. RESULTS There were strong linear associations between UPC and both clinic frequency (β = 0.94; 95% CI, 0.62-1.27) and patient load (β = -0.37; 95% CI, -0.48 to -0.26). A multiple linear regression including clinic frequency, patient load, duration in practice, and provider type explained more than 60% of the variation in UPC (adjusted R(2) = 0.629). UPC for nurse practitioners and physician assistants was more strongly dependent on clinic frequency and was at least as high as it was for physicians. Focus groups identified 6 themes as other potential sources of variability in UPC. CONCLUSIONS Variability in UPC between providers is strongly correlated with variables that can be modified by practice managers. Our study suggests that patients assigned to nurse practitioners and physician assistants have continuity similar to those assigned to physicians.