Table 1

Characteristics and cancer events for older Medicare beneficiaries with type 2 diabetes filling one or more insulin prescription during 2006–2007: overall and by insulin treatment category

TotalGlargine insulinNonglargine insulinCombination
N (%)81,681 (100.0)16,945 (20.7)49,455 (60.5)15,281 (18.7)
Age (years)77.4 ± 6.576.9 ± 6.477.6 ± 6.677.5 ± 6.6
Follow-up (months)23.2 ± 10.523.8 ± 10.223.2 ± 10.522.5 ± 10.8
Female sex56,021 (68.6)10,857 (64.1)34,789 (70.3)10,375 (67.9)
Race/ethnicity
 Black13,954 (17.1)2,363 (13.9)9,763 (19.7)1,828 (12.0)
 Hispanic7,997 (9.8)1,626 (9.6)5,229 (10.6)1,142 (7.5)
 Other59,730 (73.1)12,956 (76.5)34,463 (69.7)12,311 (80.6)
Estimated median household income (U.S. $)39,762 ± 14,66940,114 ± 14,95539,200 ± 14,39341,184 ± 15,118
Part D low-income subsidy47,807 (58.5)8,532 (50.4)30,519 (61.7)8,756 (57.3)
Diabetes complications
 0–159,150 (72.4)12,903 (76.1)36,050 (72.9)10,197 (66.7)
 214,215 (17.4)2,688 (15.9)8,470 (17.1)3,057 (20.0)
 3+8,316 (10.2)1,354 (8.0)4,935 (10.0)2,027 (13.3)
Charlson comorbidities
 020,366 (24.9)4,807 (28.4)12,530 (25.3)3,029 (19.8)
 1–345,752 (56.0)9,378 (55.3)27,770 (56.0)8,674 (56.8)
 ≥415,563 (19.1)2,760 (16.3)9,225 (18.7)3,578 (23.4)
Tobacco exposure (N [%])22,310 (27.31)4,393 (25.93)4,649 (30.42)13,268 (26.83)
Insulin daily dose67.1 ± 37.152.7 ± 31.173.4 ± 38.762.7 ± 32.5
Metformin use15,286 (18.7)4,674 (27.6)8,323 (16.8)2,289 (15.0)
Metformin daily dose (for those on metformin)1,471 ± 5781,578 ± 5681,421 ± 5761,436 ± 573
Cancer diagnosis in 36-month look back
 None72,314 (87.3)14,894 (86.5)43,959 (87.7)13,461 (86.8)
 Breast1,835 (2.2)319 (1.9)1,170 (2.3)346 (2.2)
 Colon815 (1.0)188 (1.1)455 (0.9)172 (1.1)
 Pancreas134 (0.2)28 (0.2)69 (0.1)37 (0.2)
 Prostate2,072 (2.5)519 (3.0)1,174 (2.3)379 (2.4)
 Other anatomically specific5,678 (6.9)1,277 (7.4)3,280 (6.5)1,121 (7.2)
  • Data are means ± SD or n (%). Age is at time of meeting inclusion criteria. Race/ethnicity groups are obtained from Medicare Denominator file (Research Triangle Institute) race indicator variable. Part D low-income subsidy is an indicator of income <150% of federal poverty level. Estimated median household income is based on ZIP code level 2000 census data. Diabetes complications include diagnosis of diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, and diabetic peripheral vascular disease. Charlson comorbidities from the 1987 Journal of Chronic Disease (21), modified to exclude diabetes, cancer, and tobacco use. Tobacco-related lung disease is included separately in combination with tobacco use diagnosis as the tobacco exposure variable. χ2 and F tests were used for statistical testing of any significant difference across groups. The distribution of each category of characteristics and comorbidities was significantly different across groups, with P < 0.0001 for all. Distribution of cancer events during look back was not significantly different across treatment groups (P > 0.05).