Risk factors for hypoxia and tachypnea among adolescents with vertically-acquired HIV in Nairobi
Chronic lung diseases are increasingly recognized as a complication of vertically-acquired HIV among adolescents in sub-Saharan Africa. These lung diseases may manifest with low oxygen saturation (hypoxia) or elevated respiratory rate (tachypnea). We sought to determine the prevalence of and risk factors for hypoxia and tachypnea among adolescents with vertically-acquired HIV in Nairobi, Kenya.
We performed a cross-sectional analysis of 258 adolescents (10-16.9 years old) with vertically-acquired HIV who were initiating care at the Coptic Hope Center for Infectious Diseases in Nairobi from January 2004 through June 2013. Adolescents with documented pneumonia were excluded. Hypoxia was defined as resting oxygen saturation ≤92%, and tachypnea was based on the 99th percentile of age-appropriate normal respiratory rates. Logistic regression models determined crude and adjusted odds ratios (ORs) for risk of hypoxia and tachypnea associated with potential risk factors, including age, gender, advanced HIV (WHO clinical stage 3/4), low CD4+ count (<200 cells/µL), current antiretroviral therapy (ART) and co-trimoxazole use, and BMI-for-age and height-for-age Z-scores <-2 (malnutrition and stunting, respectively). Final models included adjustment for demographics and HIV severity.
Overall, 11% of adolescents with vertically-acquired HIV had hypoxia and 55% had tachypnea at rest. Among those with hypoxia, 12 of 22 (55%) had advanced HIV and 10 of 22 (45%) had low CD4+ cell count. Advanced HIV (adjusted OR [aOR] 2.41) and low CD4+ (aOR 1.74) were associated with greater risk for hypoxia, but confidence intervals (CI) were wide and included the null (95% CI 0.93-6.23 and 0.69-4.39, respectively). Low CD4+ (aOR 2.45, 95% CI 1.39-4.32), current ART use (aOR 0.48, 95% CI 0.27-0.86) and stunted growth (aOR 3.46, 95% CI 1.94-6.18) were associated with tachypnea risk.
Hypoxia and tachypnea were common among adolescents with vertically-acquired HIV. There was a suggestion that advanced HIV and low CD4+ count were associated with a greater risk of hypoxia. Low CD4+, lack of ART use and stunted growth were risk factors for tachypnea. Our results point to potentially important risk factors that may provide mechanistic insights into the development of hypoxia and tachypnea. Further studies are needed to understand the clinical implications of these respiratory abnormalities.