. Author manuscript; available in PMC: 2016 Jun 6.

Published in final edited form as: J Am Geriatr Soc. 2015 May 8;63(5):893–901. doi: 10.1111/jgs.13388

Table 4.

Inverse Probability Treatment Weight–Adjusted Average Total Direct Medical Costs and Parameter Estimates of Insulin Initiation Categories from Ordinary Least Squares (OLS) Regression of Logged Total Direct Medical Costs (2011 USD) at 1-Year Follow-Up in Older Medicare Beneficiaries with Type 2 Diabetes Mellitus: Humana Medicare Advantage Prescription Drug Database (N = 14,669)

Insulin Initiation Categories, Number of Oral Antidiabetes Drugs	n	Costs, USD		OLS Regression
	n	Mean	Median (SE)	β (SE)	P-Value
1	4,702	17,511	8,567 (370.38)	0.02 (0.02)	.31

2	6,980	16,125	8,277 (259.06)	−0.00 (0.02)	.67

≥3	2,987	15,427	8,239 (381.25)	Reference

SE = standard error.

Mean and regression model are adjusted for inverse probability treatment weights (IPTWs), and regression model is controlled for clinical (complexities specific to older adults, adapted Diabetes Complications Severity Index, co-occurring conditions, any baseline hypoglycemia events), demographic (sex, race, region), and insurance (Medicare prescription drug, coverage gap status, type of insurance plan) characteristics, and year of observation.