Abstract
Objectives: To estimate the prevalence of and factors associated with inertia among patients with diabetes.
Methods: Using automated clinical and pharmacy data, we identified an insured cohort of patients with diabetes at the time they initiated oral monotherapy during the period, 2000–2005 (n=5082). Actuarial methods were used to estimate time to inertia (defined as 2 HbA1c values over 8% at least 90 days apart, not yet dispensed insulin with no medication change in the preceding 90 days). Among the subset facing inertia (n=1391), actuarial methods and Cox regression were used to estimate time to and factors associated with appropriate care defined as either a medication intensification (dose change, class change, or class addition) or an HbA1c <7%.
Results: At inception, mean age of the cohort was 60.1 years, mean HbA1c was 8.6% and 97% were dispensed either Sulfonylurea or Metformin. Forty-eight percent were female and 37% African American. Eight percent of patients faced inertia within 1 year, 18% within 2 years, 26% within 3 years and 33% within 4 years. Before the time of inertia, 35% had been dispensed combination therapy. At the time of inertia, 20% had no medication on hand (i.e., were non-persistent in their medication use) and mean HbA1c was 9.7% (range 8.1%–18.9%). Mean time to appropriate care was 7.3 months, with 27% having neither an intensification nor HbA1c <7% within 1 year. Those with no medication on hand (hazard ratio (HR)=0.67; 95% CI, 0.56–0.82) and those who had progressed to combination therapy (HR=0.86; 95% CI, 0.76–0.98) faced longer delays. Increased delays were also associated with increasing drug co-payments (HR=0.95; 95% CI, 0.92–0.98). HbA1c levels greater than 11% (HR=1.48; 95% CI, 1.11–1.97) were associated with shorter delays, as were dispensings for an anti-hypertensive (HR=1.17; 95% CI, 1.01–1.37), lipid lowering (HR=1.19; 95% CI, 1.03–1.37), and anti-depressant (HR=1.46; 95% CI, 1.17–1.82) medication. Increasing visit frequency to primary care (HR=1.85; 95% CI, 1.58–2.18) and endocrinology (HR=2.08; 95% CI, 1.45–2.97) were associated with decreasing delays, as were increasing income levels (HR=1.04; 95% CI, 1.00–1.07).
Conclusions: Patients with diabetes facing inertia are at risk of further delays in appropriate management. Our findings suggest the presence of patient, physician and system barriers to appropriate care. Increased contact with the health care system may mitigate risk.
- Received September 11, 2008.
