Continuity of care with a primary care physician and mortality in older adults.

BACKGROUND: We examined whether older adults who had continuity of care with a primary care physician (PCP) had lower mortality.
METHODS: Secondary analyses were conducted using baseline interview data (1993-1994) from the nationally representative Survey on Assets and Health Dynamics among the Oldest Old (AHEAD). The analytic sample included 5,457 self-respondents 70 years old or more who were not enrolled in managed care plans. AHEAD data were linked to Medicare claims for 1991-2005, providing up to 12 years of follow-up. Two time-dependent measures of continuity addressed whether there was more than an 8-month interval between any two visits to the same PCP during the prior 2-year period. The "present exposure" measure calculated this criterion on a daily basis and could switch "on" or "off" daily, whereas the "cumulative exposure" measure reflected the percentage of follow-up days, also on a daily basis allowing it to switch on or off daily, for which the criterion was met.
RESULTS: Two thousand nine hundred and fifty-four (54%) participants died during the follow-up period. Using the cumulative exposure measure, 27% never had continuity of care, whereas 31%, 20%, 14%, and 8%, respectively, had continuity for 1%-33%, 34%-67%, 68%-99%, and 100% of their follow-up days. Adjusted for demographics, socioeconomic status, social support, health lifestyle, and morbidity, both measures of continuity were associated (p < .001) with lower mortality (adjusted hazard ratios of 0.84 for the present exposure measure and 0.31, 0.39, 0.46, and 0.62, respectively, for the 1%-33%, 34%-67%, 68%-99%, and 100% categories of the cumulative exposure measure).
CONCLUSION: Continuity of care with a PCP, as assessed by two distinct measures, was associated with substantial reductions in long-term mortality.