Biologic therapy is not associated with increased COVID-19 severity in patients with hidradenitis suppurativa: Initial findings from the Global Hidradenitis Suppurativa COVID-19 Registry.

To the Editor: Hidradenitis suppurativa (HS) patients may be at increased risk of severe COVID-19 and poor outcomes due to comorbidities and biologic treatment. COVID-19 cases in HS patients were reported in the Global Hidradenitis Suppurativa COVID-19 Registry (https://hscovid.ucsf.edu/) from April 5, 2020, to February 2, 2021. Eligible cases had confirmed diagnosis of HS by a health care provider (HCP) or screening questions and COVID-19 diagnosis by an HCP. Comparisons were performed using the Fisher's exact or Pearson χ2 test. Multivariable logistic regression was used to predict outcomes based on biologic use, adjusting for demographic features and comorbidities.

One hundred ninety-two and 44 cases were entered in the patient and HCP registries, respectively. Forty self-reported cases were incomplete. The descriptive characteristics of 135 eligible self-reported and 44 eligible HCP-reported cases are presented in Table I . Tumor necrosis factor inhibitors were the most commonly used biologic (self-reported: 22/25, 88.0%; and HCP: 19/22, 86.3%). No myocardial infarctions, strokes, or deaths were reported.

Table I

Patient characteristics

Characteristics	Patient/Caregiver-reported cases			Health care provider-reported cases
	Biologic	No biologic	All	Biologic	No biologic	All
Number	25	110	135	22	22	44
Age, y (median, IQR)	34 (32-46)	31 (26-39)	33 (26-41)	34 (27-42)	33 (28-39)	33.5 (27.5-41)
Female sex	22 (88.0%)	100 (90.9%)	122 (90.4%)	13 (59.1%)	15 (71.4%)	28 (65.1%)
Race/ethnicity
White	16 (64.0%)	79 (71.8%)	95 (70.4%)	11 (50.0%)	7 (31.8%)	18 (40.9%)
Black African	2 (8.0%)	2 (1.8%)	4 (3.0%)	0 (0%)	4 (18.2%)	4 (9.1%)
Black African American	2 (8.0%)	3 (2.8%)	5 (3.7%)	4 (18.2%)	1 (4.6%)	5 (11.4%)
Asian	0 (0%)	1 (0.9%)	1 (0.7%)	1 (4.6%)	1 (4.6%)	2 (4.5%)
Hispanic	3 (12.0%)	13 (11.8%)	16 (11.8%)	3 (13.6%)	1 (4.6%)	4 (9.1%)
Mixed race	2 (8.0%)	8 (7.3%)	10 (7.4%)	0 (0%)	2 (9.1%)	2 (4.6%)
Other	0 (0%)	4 (3.7%)	4 (3.0%)	2 (9.1%)	3 (13.6%)	5 (11.4%)
Country
United States	22 (88.0%)	56 (50.9%)	78 (57.8%)	8 (36.4%)	5 (22.7%)	13 (29.6%)
United Kingdom	1 (4.0%)	14 (12.7%)	15 (11.1%)	5 (22.7%)	3 (13.6%)	8 (18.2%)
Brazil	0 (0%)	15 (13.6%)	15 (11.1%)	1 (4.6%)	0 (0%)	1 (2.3%)
Sweden	0 (0%)	13 (11.8%)	13 (9.6%)	−	−	−
France	−	−	−	1 (4.6%)	10 (45.5%)	11 (25.0%)
Italy	−	−	−	4 (18.2%)	1 (4.6%)	5 (11.4%)
Other	11 (10.1%)	2 (8.0%)	13 (9.7%)∗	3 (13.7%)	3 (13.7%)	6 (13.7%)†
Comorbidities
Obesity	17 (68.0%)	72 (65.5%)	89 (65.9%)	7 (31.8%)	6 (27.3%)	13 (29.6%)
Diabetes	1 (4.0%)	4 (3.6%)	5 (3.7%)	4 (18.2%)	2 (9.1%)	6 (13.7%)
Pulmonary disease	10 (40.0%)	22 (20.0%)	32 (23.7%)	2 (9.1%)	2 (9.1%)	4 (9.1%)
Tobacco smoking	4 (16.0%)	19 (17.3%)	23 (17.0%)	−	−	−
CV disease	1 (4.0%)	3 (2.7%)	4 (3.0%)	2 (9.1%)	0 (0%)	2 (4.6%)
Hurley stage
Hurley 1	3 (12.0%)	26 (23.6%)	29 (21.5%)	2 (9.1%)	5 (22.7%)	7 (15.9%)
Hurley 2	11 (44.0%)	49 (45.5%)	60 (45.2%)	7 (31.8%)	10 (45.6%)	17 (38.6%)
Hurley 3	9 (36.0%)	21 (19.1%)	30 (22.2%)	13 (59.1%)	7 (31.8%)	20 (45.5%)
Unknown	2 (8.0%)	13 (11.8%)	15 (11.1%)	−	−	−

CV, Cardiovascular; IQR, interquartile range.

Other category includes 1-3 cases each from Argentina, Austria, Canada, Denmark, Ireland, Peru, Saudi Arabia, and Spain.

Other category includes 1-2 cases each from Argentina, Canada, Czech Republic, Israel, and Saudi Arabia.

Among the self-reported cases, the odds of hospitalization (biologic: 3/25 [12%]; nonbiologic: 19/110 [17.4%], odds ratio 0.34, P = .16) or oxygen requirement (biologic: 5/25 (20%); nonbiologic: 28/110 (25.5%), odds ratio 0.6, P = .37) were not greater with biologics. No complications occurred in 49.3% of the patients, and 64.9% required no COVID-19 treatment. Patients on biologic therapy reported dyspnea less frequently (biologic 1/25, 4.0%; nonbiologic 23/110, 20.9%, P = .04) but showed a trend toward increased HS flares (biologic 12/25, 48.0%; nonbiologic 32/110, 29.4%, P = .07) and longer time to COVID-19 resolution (biologic: median (interquartile range) 21 (14-31) days; nonbiologic: 14 (9-25) days, P = .07). Two cases of pneumonias, 1 of sepsis, and 1 of pulmonary embolism were reported, all in patients on nonbiologic therapy. There were no differences in treatment location (P = .6) or complications (P > .1 for all) between those who continued biologics and those who discontinued biologics.

Among the HCP-reported cases, 78.1% (32/44) had mild COVID-19, and no differences in severity were seen between those on biologics and those on nonbiologics (P = .2) and between those who continued biologics versus those who discontinued biologics (P = .9). No complications were experienced by 86.4% (38/44) of the patients, and 84.1% (37/44) required no COVID-19 treatment. Dyspnea was experienced by 11.4% (5/44), but there was no difference in complications (P = .3) or COVID-19 treatment (P = .5) between patients on biologic therapy and those on nonbiologic therapy. We were insufficiently powered to assess differences in COVID-19 severity across age or comorbidities in either the self- or HCP-reported cases.

Our initial findings extend previous limited reports. One Italian survey did not detect COVID-19 among 96 HS patients, 59.4% of whom were on biologics, whereas another confirmed 3 COVID-19 cases among 311 HS patients taking adalimumab. None were hospitalized, and all fully recovered. A Spanish study found that 2 of 8 HS patients with COVID-19 symptoms were on adalimumab, and neither developed pneumonia or required hospitalization. A US study reported 39 HS patients with confirmed COVID-19. Eight (20.5%) were hospitalized, and one 60-year-old patient not on systemic treatments for HS died. Male sex, antibiotic treatment, diabetes, and increased mean age were associated with hospitalization. One patient on infliximab had a mild COVID-19 course and did not require hospitalization.

Despite sample size limitations, possible missed cases, and potential recall bias, this is the largest report of COVID-19 outcomes in an international HS population. These data provide valuable information to guide patient care during and after the pandemic.

Conflicts of interest

Dr Naik has received grant support from AbbVie, consulting fees from 23andme, advisory board fees from Invitrogen Biovitrum; has served as an investigator for Pfizer; and is a board member of the US Hidradenitis Suppurativa Foundation. Dr Alhusayen has received fees for participating in advisory boards for AbbVie and Janssen, has received consulting fees from Eli Lilly and Hidramed solutions, and is the President of the Canadian Hidradenitis Suppurativa Foundation. Author Ingram has received fees for participating in advisory boards for Viela Bio and Kymera Therapeutics; consulting fees from UCB Pharma, Novartis, ChemoCentryx, and Boehringer Ingelheim; editorial honorarium as BJD Editor-in-Chief; royalties as chapter author for UpToDate; and co-copyright holder for the HiSQOL, HS Patient Global Assessment, HS Investigator Global Assessment. He received travel expenses and a speaker's honorarium from UCB Pharma. Dr Lowes has received fees for participating in advisory boards for AbbVie, Janssen, Viela Bio and consulting fees from Incyte, BSN, XBiotech, Kymera, and Almirall and is the Vice President of the US Hidradenitis Suppurativa Foundation. Author Guilbault has received compensation for patient advisory board from Boehringer Ingelheim and is a board member of the US HS Foundation and Hope for HS. Author Vilumsen has received compensation for patient advisory board from Boehringer Ingelheim and consulting fee for UCB and is the President of Patientforeningen HS Danmark. Drs Frew and Marzano and Authors Paul and Yannuzzi have no conflicts of interest to declare.