HSR&D Citation Abstract
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Isolated abnormal diffusing capacity for carbon monoxide (iso DLco) is associated with increased respiratory symptom burden in people with HIV infection.
Byanova KL, Fitzpatrick J, Jan AK, McGing M, Hartman-Filson M, Farr CK, Zhang M, Gardner K, Branchini J, Kerruish R, Bhide S, Bates A, Hsieh J, Abelman R, Hunt PW, Wang RJ, Crothers KA, Huang L. Isolated abnormal diffusing capacity for carbon monoxide (iso DLco) is associated with increased respiratory symptom burden in people with HIV infection. PLoS ONE. 2023 Jul 18; 18(7):e0288803.
An isolated reduction in the diffusing capacity for carbon monoxide (DLco; iso DLco) is one of the most common pulmonary function test (PFT) abnormalities in people living with HIV (PWH), but its clinical implications are incompletely understood. In this study, we explored whether iso DLco in PWH is associated with a greater respiratory symptom burden.
We used ATS/ERS compliant PFTs from PWH with normal spirometry (post-bronchodilator FEV1/FVC 0.7; FEV1, FVC 80% predicted) from the I AM OLD cohort in San Francisco, CA and Seattle, WA, grouped by DLco categorized as normal (DLco lower limit of normal, LLN), mild iso DLco (LLN > DLco > 60% predicted), and moderate-severe iso DLco (DLco 60% predicted). We performed multivariable analyses to test for associations between DLco and validated symptom-severity and quality of life questionnaires, including the modified Medical Research Council dyspnea scale (mMRC), the COPD Assessment Test (CAT), and St. George's Respiratory Questionnaire (SGRQ), as well as between DLco and individual CAT symptoms.
Mild iso DLco was associated only with a significantly higher SGRQ score. Moderate-severe iso DLco was associated with significantly higher odds of mMRC 2 and significantly higher CAT and SGRQ scores. PWH with moderate-severe iso DLco had increased odds of breathlessness, decreased activity, lower confidence leaving home, and less energy.
Iso DLco is associated with worse respiratory symptom scores, and this association becomes stronger with worsening DLco, suggesting that impaired gas exchange alone has a significant negative impact on the quality of life in PWH. Additional studies are ongoing to understand the etiology of this finding and design appropriate interventions.