Factors associated with time to follow-up of severe hyperkalemia in the ambulatory setting

Background. Few studies have investigated the time it takes physicians to follow up abnormal outpatient laboratory results. Methods. Medical record review of all adult patients seen at a primary care practice between January 2002 and December 2005 with serum potassium results < 6.0 mEq/L. We used a proportional hazards model to assess factors associated with time to follow-up for episodes of hyperkalemia. Results. 259 of 48 333 serum potassium results met inclusion criteria. The median follow-up time was 3 days; after 30 days, 10% of cases had no follow-up. Residing in the same zip code as the clinic (HR = 1.39; P =.029), degree of hyperkalemia (HR = 2.97; P < .001), and renal insufficiency (HR = 1.41; P =.015) were associated with decreased time to repeat testing. Conversely, African Americans (HR =.51; P =.007) had increased time to repeat testing. Conclusions. Follow-up of abnormal laboratory results in outpatients is suboptimal and research is needed to better understand factors that delay follow-up.