Research Article: HIV infection is an independent risk factor for decreased 6-minute walk test distance

Date Published: April 24, 2019

Publisher: Public Library of Science

Author(s): Tom E. Robertson, Mehdi Nouraie, Shulin Qin, Kristina A. Crothers, Cathy J. Kessinger, Deborah McMahon, Divay Chandra, Lawrence A. Kingsley, Ruth M. Greenblatt, Laurence Huang, Meghan E. Fitzpatrick, Alison Morris, James West.


Ambulatory function predicts morbidity and mortality and may be influenced by cardiopulmonary dysfunction. Persons living with HIV (PLWH) suffer from a high prevalence of cardiac and pulmonary comorbidities that may contribute to higher risk of ambulatory dysfunction as measured by 6-minute walk test distance (6-MWD). We investigated the effect of HIV on 6-MWD.

PLWH and HIV-uninfected individuals were enrolled from 2 clinical centers and completed a 6-MWD, spirometry, diffusing capacity for carbon monoxide (DLCO) and St. George’s Respiratory Questionnaire (SGRQ). Results of 6-MWD were compared between PLWH and uninfected individuals after adjusting for confounders. Multivariable linear regression analysis was used to determine predictors of 6-MWD.

Mean 6-MWD in PLWH was 431 meters versus 462 in 130 HIV-uninfected individuals (p = 0.0001). Older age, lower forced expiratory volume (FEV1)% or lower forced vital capacity (FVC)%, and smoking were significant predictors of decreased 6-MWD in PLWH, but not HIV-uninfected individuals. Lower DLCO% and higher SGRQ were associated with lower 6-MWD in both groups. In a combined model, HIV status remained an independent predictor of decreased 6-MWD (Mean difference = -19.9 meters, p = 0.005).

HIV infection was associated with decreased ambulatory function. Airflow limitation and impaired diffusion capacity can partially explain this effect. Subjective assessments of respiratory symptoms may identify individuals at risk for impaired physical function who may benefit from early intervention.

Partial Text

Half of persons living with HIV (PLWH) living in the United States are over 50 years old [1] and are increasingly affected by age-associated and chronic comorbid conditions [2, 3]. HIV infection is similarly associated with increased frailty, as well as declines in lung and cardiovascular health [4] that have potential impact on physical function. In one large study of United States male veterans, decline in scale-based self-reported physical function per year was greater in PLWH than HIV-uninfected individuals, and chronic pulmonary disease appeared to uniquely modify this effect [5]. While there have been a host of studies assessing chronic pulmonary disease and aberrant pulmonary physiology in PLWH [6–8], there has been limited research specifically assessing cardiopulmonary functional capacity, highlighting the lack of insight into the clinical determinants of declining physical function in this high-risk group [9]. Additionally, in heterogenous populations of PLWH, the relationships among demographic and clinical variables and measures of physical function are relatively unexplored [10].

We evaluated the relationships of HIV status, demographic and clinical variables, standardized respiratory questionnaires, and pulmonary function with 6-MWD in a cohort of PLWH and HIV-uninfected individuals. Although the majority of the cohort was virally-suppressed, HIV infection had an independent association with decreased 6-MWD, with average 6-MWD for PLWH approximately 20 meters less than for HIV-uninfected individuals when adjusted for covariates. We found that severity of airflow limitation and diffusing capacity impairment were independent predictors of decreased 6-MWD in PLWH, with only diffusing impairment being associated with 6-MWD in HIV-uninfected individuals. Worse SGRQ predicted shorter 6-MWD in both groups. HIV-associated variables such as CD4 cell count and ART use were not associated with 6-MWD.




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