Human immunodeficiency virus patients with low CD4 counts are more likely to have precancerous polyps identified during index colonoscopy.

Abstract

Background: Antiretroviral treatment (ART) has improved the life expectancy of patients living with human immunodeficiency virus (HIV). As these patients age, they are at increased risk for developing non-acquired immunodeficiency syndrome defining malignancies (NADMs) such as colon cancers.

Aim: To determine which factors are associated with the development of precancerous polyps on screening colonoscopy in patients with HIV and to investigate whether HIV disease status, measured by viral load and CD4 count, might influence precancerous polyp development.

Methods: A retrospective review of records at two urban academic medical centers was performed for HIV patients who had a screening colonoscopy between 2005-2015. Patients with a history of colorectal cancer or polyps, poor bowel preparation, or inflammatory bowel disease were excluded. Demographic data such as sex, age, race, and body mass index (BMI) as well as information regarding the HIV disease status such as CD4 count, viral load, and medication regimen were collected. Well-controlled patients were defined as those that had viral load < 50 copies, and poorly-controlled patients were those with viral load ≥ 50. Patients were also stratified based on their CD4 count, comparing those with a low CD4 count to those with a high CD4 count. Using colonoscopy reports in the medical record, the size, histology, and number of polyps were recorded for each patient. Precancerous polyps included adenomas and proximal serrated polyps. Data was analyzed using Fisher's exact tests and logistic regression through SAS 3.8 software.

Results: Two hundred and seven patients met our inclusion criteria. The mean age was 56.13 years, and 58% were males. There were no significant differences in terms of age, race or ethnicity, insurance, and smoking status between patients with CD4 counts above or below 500. BMI was lower in patients with CD4 count < 500 as compared to those with count > 500 (P = 0.0276). In patients with CD4 > 500, 53.85% of patients were female, and 70.87% of patients with CD4 < 500 were male (P = 0.0004). Only 1.92% of patients with CD4 ≥ 500 had precancerous polyps vs 10.68% of patients with CD4 < 500 (P = 0.0102). When controlled for sex, BMI, and ART use, patients with CD4 < 500 were 9.01 times more likely to have precancerous polyps [95% confidence interval (CI): 1.69-47.97; P = 0.0100]. Patients taking non-nucleoside reverse transcriptase inhibitors were also found to be 10.23 times more likely to have precancerous polyps (95%CI: 1.08-97.15; P = 0.0428). There was not a significant difference noted in precancerous polyps between those that had viral loads greater or less than 50 copies.

Conclusion: Patients with low CD4 counts were more likely to have precancerous polyps on their screening colonoscopy although the etiology for this association is unclear. We also found an increased risk of precancerous polyps in patients taking non-nucleoside reverse transcriptase inhibitors, which is contradictory to prior literature showing ART has decreased the risk of development of NADMs. However, there have not been studies looking at colorectal cancer and ART by drug class, to our knowledge. Further prospective studies are needed to determine the effect of HIV control and therapies on polyp development.