US study of HIV positive people with COVID-19 reports worse outcomes with comorbidities and having a CD4 <200
A large prospective US study on COVID-19 in people living with HIV has reported worse outcomes associated with multiple comorbidities. It also reports a link to lower CD4 counts that has not been seen in other studies, even when on effective ART. 
This study, published on 9 September 2020 in Clinical Infectious Diseases, included 286 participants diagnosed with confirmed COVID-19 between 1 April and 1 July 2020. Cases were submitted by a range of 36 US medical providers from 21 States to a multicentre registry at University of Missouri. Just under half these cases (47%) were from the US South. Three international centres also reported 21 cases. Multivariate analyses were run to determine risk factors for worse outcomes.
The mean age was 51.4 years (SD: 14.4), 26% were female, and 47.5% were African-American and 28% were Hispanic. Most patients (94%) were on ART, 89% had HIV virologic suppression, and mean CD4 counts was 531 cells/mm3(SD 340). Five duplicate cases were removed.
Overall, 81% had significant comorbidities including hypertension (46%), obesity (32%), and diabetes (21%).
Within 30 days of confirmed COVID-19, 164 (57%) patients were hospitalised and 47 (16.5%) required ICU admission. Mortality rates were 9.4% (27/286) overall, 16.5% (27/164) among those hospitalised, and 51.5% (24/47) among those admitted to an ICU. The primary composite endpoint of ICU admission, mechanical ventilation or death occurred in 17.5% (50/286) overall and in 30.5% (50/164) of those hospitalised.
Hospitalisation was associated with older age (p<0.01), lower CD4 counts (p<0.01), number of years living with HIV (p<0.01), not being on ART (p=0.04) or being virally suppressed (p=0.02), and high comorbidity burden (p<0.01).
Multivariate analysis showed older age (p=0.02), CD4 count <200 (p=0.05), chronic lung disease (p<0.01), hypertension (p=0.01), and high (3+) comorbidity burden (p=0.05) were significantly associated with severe outcomes.
Based on 47 participants admitted to an ICU and 27 who died, CD4 cell count had a significant effect on survival. Having a CD4 count <200 vs >500 cells/mm3was significantly related to both lower ICU-free survival (p=0.04) and overall survival (p=0.05).
Although submission to the registry may have included selection bias, the paper notes that 17/36 clinics included all cases of COVID-19 diagnosis. Other limitations for this study included limited data on steroid use and enrollment in COVID-19 research studies.
The researchers reported that the rates of ICU admission, use of mechanical ventilation, and mortality among HIV positive people with COVID-19 were similar to US general population data. Sensitivity analyses using only US participants did not affect the overall results.
However, this is the largest study to report an association between lower CD4 counts (<200) and worse primary and secondary outcomes from COVID-19, irrespective of viral suppression on ART. These data also disprove and early hypothesis that immune dysfunction might be protective of COVID-19.
An earlier US case-control study reporting a link to lower CD4 count only included 21 HIV positive people. 
- Dandachi D et al. Characteristics, comorbidities, and outcomes in a multicenter registry of patients with HIV and coronavirus disease-19. Clinical Infectious Diseases, ciaa1339, DOI: 10.1093/cid/ciaa1339. (09 September 2020).
- Karmen-Tuohy S et al. Outcomes among HIV-positive patients hospitalized with COVID-19. JAIDS. DOI: 10.1097/QAI.0000000000002423.