HIV infection status, immunodeficiency, and the incidence of non-melanoma skin cancer

Abstract

Background The incidence of non-melanoma skin cancers (NMSCs), including basal cell (BCC) or squamous cell carcinoma (SCC), is not well documented among HIV-positive (HIV(+)) individuals. Methods We identified 6560 HIV(+) and 36 821 HIV-negative (HIV(-)) non-Hispanic white adults who were enrolled and followed up in Kaiser Permanente Northern California from 1996 to 2008. The first biopsy-proven NMSCs diagnosed during follow-up were identified from pathology records. Poisson models estimated rate ratios that compared HIV(+) (overall and stratified by recent CD4 T-cell counts and serum HIV RNA levels) with HIV(-) subjects and were adjusted for age, sex, smoking history, obesity diagnosis history, and census-based household income. Sensitivity analyses were adjusted for outpatient visits (ie, a proxy for screening). All statistical tests were two-sided. Results The NMSC incidence rate was 1426 and 766 per 100 000 person-years for HIV(+) and HIV(-) individuals, respectively, which corresponds with an adjusted rate ratio of 2.1 (95% confidence interval [CI] = 1.9 to 2.3). Similarly, the adjusted rate ratio for HIV(+) vs HIV(-) subjects was 2.6 (95% CI = 2.1 to 3.2) for SCCs, and it was 2.1 (95% CI = 1.8 to 2.3) for BCCs. There was a statistically significant trend of higher rate ratios with lower recent CD4 counts among HIV(+) subjects compared with HIV(-) subjects for SCCs (P trend < .001). Adjustment for number of outpatient visits did not affect the results. Conclusion HIV(+) subjects had a twofold higher incidence rate of NMSCs compared with HIV(-) subjects. SCCs but not BCCs were associated with immunodeficiency.

Figure 1.

Rate ratios (and 95% confidence intervals [CIs]) for non-melanoma skin cancer by recent CD4 counts among HIV-positive (HIV⁺) subjects compared with HIV-negative (HIV⁻) subjects. Rate ratios are from Poisson regression models with terms for HIV status/recent CD4 counts (HIV⁻ reference), age, sex, smoking, overweight/obesity, and 2000 Census-based income levels. Two-sided P value tests trend in rate ratios over CD4 count strata are by the likelihood ratio test. Results are shown separately for non-melanoma skin cancer (NMSC, left panel), basal cell carcinoma (BCC, middle panel), and squamous cell carcinoma (SCC, right panel). The black squares correspond with rate ratio point estimates, the vertical solid lines correspond with 95% confidence intervals, and the dashed horizontal line corresponds with a rate ratio of 1.0.