Table 2.

Multivariate linear regression analysis: annual mean GHb modeled as a function of periodontitis status in diabetic patients with medical and dental insurance, age 40–77 years, and at least one medical and dental visit during the 5-year study period

	n	Difference in mean GHb among patients who did and did not receive periodontal care	P	Lower CI	Upper CI
Unadjusted	5,103	0.11	0.005	0.03	0.19
Age, BMI, and sex adjusted	5,102	0.09	0.02	0.01	0.17
Multiple adjustment*	5,099	0.08	0.04	0.005	0.16
Multiple adjustment and controlling for severity of diabetes†	5,099	0.08	0.02	0.01	0.15

*Covariates included in model: age, BMI, sex, RxRisk in 2002, smoking status, number of primary care visits (square root), number of specialty care visits (square root), number of well visits (square root), and number of GHb tests (square root).

†In addition to covariates mentioned above, this model also included diabetes treatment level (no medication for diabetes, oral glycemic medication only, or any insulin) and Diabetes Complication Severity Index variables.