Further exploration of the relationship between insulin glargine and incident cancer: A retrospective cohort study of older medicare patients

Nancy E. Morden, Stephen K. Liu, Jeremy Smith, Todd A. Mackenzie, Jonathan Skinner, Murray Korc

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

OBJECTIVE - In vitro evidence suggests insulin glargine promotes tumors; observational human studies are conflicting. We aimed to expand understanding of this potential treatment risk. RESEARCH DESIGN AND METHODS - This retrospective cohort study of type 2 diabetic patients >68 years old used Medicare inpatient, outpatient (2003-2008), and prescription data (2006-2008). Adjusting for patient characteristics, dose, and metformin use, Cox models yielded hazard ratios (HRs) for incident cancer (breast, prostate, pancreas, colon, any site) associated with three forms of insulin: nonglargine, glargine, or glargine plus nonglargine (combination). RESULTS-Overall, 81,681 patients were followed for a mean of 23.1 months. Mean age was 77.4 years. Treatment group distribution was 20.7% glargine, 60.5% nonglargine, 18.7% combination insulin. We observed 5,466 incident cancers; crude rates did not vary by treatment group. In fully adjusted models, nonglargine use was the referent; glargine was not associated with significant increased risk of any cancer measure. In secondary analyses including only the top quartile of daily insulin dose patients, glargine was not associated with any cancer risk difference; combination insulin was associated with higher breast cancer risk (HR 1.75 [95% CI 1.10-2.78]) and lower colon cancer risk (0.33 [0.13-0.80]). In age-stratified analyses of highest-dose users, combination insulin conferred a higher risk of breast cancer in those ≤75 years old (2.87 [1.45-1.59]). CONCLUSIONS-The general lack of association between glargine-only use and cancer is reassuring. Breast cancer risk associated with high-dose combination insulin in secondary analyses could result from multiple comparisons, residual confounding, or true association; further research is warranted.

Original languageEnglish (US)
Pages (from-to)1965-1971
Number of pages7
JournalDiabetes Care
Volume34
Issue number9
DOIs
StatePublished - Sep 2011
Externally publishedYes

Fingerprint

Medicare
Cohort Studies
Retrospective Studies
Insulin
Neoplasms
Breast Neoplasms
Metformin
Insulin Glargine
Proportional Hazards Models
Colonic Neoplasms
Observational Studies
Prescriptions
Inpatients
Pancreas
Prostatic Neoplasms
Colon
Research Design
Outpatients
Therapeutics
Odds Ratio

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Advanced and Specialized Nursing

Cite this

Further exploration of the relationship between insulin glargine and incident cancer : A retrospective cohort study of older medicare patients. / Morden, Nancy E.; Liu, Stephen K.; Smith, Jeremy; Mackenzie, Todd A.; Skinner, Jonathan; Korc, Murray.

In: Diabetes Care, Vol. 34, No. 9, 09.2011, p. 1965-1971.

Research output: Contribution to journalArticle

Morden, Nancy E. ; Liu, Stephen K. ; Smith, Jeremy ; Mackenzie, Todd A. ; Skinner, Jonathan ; Korc, Murray. / Further exploration of the relationship between insulin glargine and incident cancer : A retrospective cohort study of older medicare patients. In: Diabetes Care. 2011 ; Vol. 34, No. 9. pp. 1965-1971.
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abstract = "OBJECTIVE - In vitro evidence suggests insulin glargine promotes tumors; observational human studies are conflicting. We aimed to expand understanding of this potential treatment risk. RESEARCH DESIGN AND METHODS - This retrospective cohort study of type 2 diabetic patients >68 years old used Medicare inpatient, outpatient (2003-2008), and prescription data (2006-2008). Adjusting for patient characteristics, dose, and metformin use, Cox models yielded hazard ratios (HRs) for incident cancer (breast, prostate, pancreas, colon, any site) associated with three forms of insulin: nonglargine, glargine, or glargine plus nonglargine (combination). RESULTS-Overall, 81,681 patients were followed for a mean of 23.1 months. Mean age was 77.4 years. Treatment group distribution was 20.7{\%} glargine, 60.5{\%} nonglargine, 18.7{\%} combination insulin. We observed 5,466 incident cancers; crude rates did not vary by treatment group. In fully adjusted models, nonglargine use was the referent; glargine was not associated with significant increased risk of any cancer measure. In secondary analyses including only the top quartile of daily insulin dose patients, glargine was not associated with any cancer risk difference; combination insulin was associated with higher breast cancer risk (HR 1.75 [95{\%} CI 1.10-2.78]) and lower colon cancer risk (0.33 [0.13-0.80]). In age-stratified analyses of highest-dose users, combination insulin conferred a higher risk of breast cancer in those ≤75 years old (2.87 [1.45-1.59]). CONCLUSIONS-The general lack of association between glargine-only use and cancer is reassuring. Breast cancer risk associated with high-dose combination insulin in secondary analyses could result from multiple comparisons, residual confounding, or true association; further research is warranted.",
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AB - OBJECTIVE - In vitro evidence suggests insulin glargine promotes tumors; observational human studies are conflicting. We aimed to expand understanding of this potential treatment risk. RESEARCH DESIGN AND METHODS - This retrospective cohort study of type 2 diabetic patients >68 years old used Medicare inpatient, outpatient (2003-2008), and prescription data (2006-2008). Adjusting for patient characteristics, dose, and metformin use, Cox models yielded hazard ratios (HRs) for incident cancer (breast, prostate, pancreas, colon, any site) associated with three forms of insulin: nonglargine, glargine, or glargine plus nonglargine (combination). RESULTS-Overall, 81,681 patients were followed for a mean of 23.1 months. Mean age was 77.4 years. Treatment group distribution was 20.7% glargine, 60.5% nonglargine, 18.7% combination insulin. We observed 5,466 incident cancers; crude rates did not vary by treatment group. In fully adjusted models, nonglargine use was the referent; glargine was not associated with significant increased risk of any cancer measure. In secondary analyses including only the top quartile of daily insulin dose patients, glargine was not associated with any cancer risk difference; combination insulin was associated with higher breast cancer risk (HR 1.75 [95% CI 1.10-2.78]) and lower colon cancer risk (0.33 [0.13-0.80]). In age-stratified analyses of highest-dose users, combination insulin conferred a higher risk of breast cancer in those ≤75 years old (2.87 [1.45-1.59]). CONCLUSIONS-The general lack of association between glargine-only use and cancer is reassuring. Breast cancer risk associated with high-dose combination insulin in secondary analyses could result from multiple comparisons, residual confounding, or true association; further research is warranted.

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