We sought to estimate rates and predictors of completion of clinical laboratory tests by diabetes patients subsequent to provider referrals.
Prospective cohort study
Among 186,306 adult members with diabetes in Kaiser Permanente Northern California, we searched the electronic medical records (7/1/2008 – 6/30/2009) of each patient for the first outpatient order for lab tests commonly used to measure risk factor control or adverse effects of pharmacotherapy: glycosylated hemoglobin (A1c), low-density lipoprotein (LDL), serum creatinine (SC), urinary albumin (UA) or creatine kinase (CK) (CK only among persons using statins). We measured lab attendance as completion of the order within 6 months of the order date, counting the days to result, and looked for variations by subgroups.
Lab attendance ranged from 86% for A1c to 73% for SC. Time to attendance had a median of 7–10 days and mean of 25–30 days. Attendance was more likely among women, older patients or for orders subsequent to a face-to-face provider visit and less likely if ordered by a pharmacist, but most variations, even by copayment, were small or not clinically substantive. In subanalyses, we observed no clinically significant variations by race, socioeconomic status, trust in provider or patient-provider communication, and no association with depression, health literacy or English fluency.
The fact that one in seven patients did not complete labwork within six months of the provider referral may help explain why healthcare services appear to fall short of optimal diabetes care.
Keywords: diabetes mellitus, laboratory techniques and procedures, electronic health record, adherence, HbA1c