Author Affiliations: Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (Drs Butt and Freiberg); VA Pittsburgh Healthcare System, Pittsburgh (Dr Butt); and Yale University School of Medicine, New Haven, Connecticut, and VA Connecticut Healthcare System, West Haven (Dr Justice).
We thank de Melo Neto et al for their insightful comments about our article.1 We agree that using ICD-9 codes can potentially introduce a bias in any analysis using such data. We have previously validated hypertension ICD-9 codes against structured medical chart review as the gold standard.2 Among HIV-infected persons enrolled in the 3-site Veterans Aging Cohort Study, the prevalence of hypertension by ICD-9 codes and medical chart reviews was 28% and 32% respectively, with an agreement of 85.2% and a κ value of 0.65. Hence, there may have been a slight underreporting of hypertension in the HIV-infected group. We are currently evaluating whether diagnosis of hypertension differs by HIV status using actual blood pressure measurement. For diabetes, we used a combination of laboratory measurements, use of insulin and oral hypoglycemic medications, and ICD-9 codes, as used in several previous studies.3,4
Butt AA, Justice AC, Freiberg MS. Risk of Heart Failure With Human Immunodeficiency Virus Is Greater Than Hypertension?—Reply. Arch Intern Med. 2011;171(19):1773-1774. doi:10.1001/archinternmed.2011.560