Of 3,384 safety net clinic patients with diabetes, 27% had no known insurance coverage in 2005–2007, 21% had partial coverage, and 52% had continuous coverage (). Of those with only partial coverage, the average coverage was for 68% (SD 27%, range 1% – 99%) of the study period (results not shown). Most study population members were aged 19 to 65, there were more women than men, about one-third were of Hispanic origin, almost three-fourths were from households below the FPL, and nearly all were from households below 200% of the FPL. There were significant differences between the insurance coverage groups in the distribution of each of the demographic characteristics.
In the three-year study period, 48% of continuously insured persons received ≥3 LDL screenings, 25% received ≥3 flu vaccinations, 72% received ≥3 HbA1c screenings, and 19% received ≥3 nephropathy screenings, at an OCHIN clinic (). Those with partial or no coverage had significantly lower rates of receiving each service ≥1 time or ≥3 times, compared to those continuously insured.
Among the 711 persons with partial insurance coverage during the study period, 44% had coverage for 80–99% of the three-year study period, 26% for 60–79% of that time, 9% for 40–59% of the time, 12% for 20–39% of the time, and 8% for 1–19% of the study period. In almost all cases, those insured for 1–99% of the study period received services less than those continuously insured, with no pattern of differences in rate of care receipt seen between quintiles of time covered.
In multivariate logistic regression analyses comparing the odds of receiving each of the diabetes care services ≥3 times, persons with partial insurance coverage had significantly lower odds than those with continuous coverage in all four cases. Similarly, the continuously uninsured had lower odds in three of the four cases, with no significant differences as compared to the continuously insured only in receipt of ≥3 microalbumin screenings. Hispanic persons had significantly higher odds than white persons to receive ≥3 influenza vaccinations and ≥3 HbA1c screenings, and significantly lower odds of receiving ≥3 microalbumin screenings. Non-Hispanic, non-white persons had significantly higher odds than white persons of receiving ≥3 services in all four cases.
When comparing persons with different levels of partial coverage to those with continuous coverage, persons in all five quintiles were significantly less likely to receive ≥3 LDL screenings. Those with 20–99% coverage were less likely to receive >3 flu shots and >3 HgA1c screenings. Only those with 80–99% coverage were significantly less likely to receive ≥3 microalbumin screenings. Although screening rates were not significantly lower for all insurance quintiles, almost all point estimates trended in the same direction (lower odds of receiving services). Among persons insured for part of the study period, there was no evidence of a threshold of percent of time covered above which the odds of receiving appropriate care increased, nor was there evidence of a dose-response relationship between percent of time covered and receipt of care.