Cohort profile update: The Swiss HIV Cohort Study (SHCS). International Journal of Epidemiology
Scherrer et al. aimed to update the Swiss HIV Cohort Study (SHCS) cohort profile, published in 2009, because of changing characteristics of the HIV-infected population in Switzerland and changes in the focus of research within the SHCS.
In brief, the SHCS is a national, multicentre cohort continuously enrolling HIV-infected adults since 1988 to monitor the HIV epidemic in Switzerland. By the end of 2019, 20’845 were registered in one of the seven study centers (five university hospitals, two large cantonal hospitals), its affiliated 14 regional hospitals or with its affiliated 48 private physicians. Overall, 5’697 (27.3%) women were included, including 2’726 under follow-up in 2019. Homosexual contact was reported as the presumed mode of HIV transmission in 8’169 (39.2%) of all included patients (46.8% of patients seen in 2019) and 6’881 (33.0%) persons were infected heterosexually (37.9% of patients seen in 2019). Only 966 (9.9%) of patients seen in 2019 were infected through intravenous drug use; in all patients the percentage was 23.2% (n=4’834).
Overall 15’076 (72.3%) patients have received combined antiretroviral treatment (cART, three or more drugs from at least two drug classes) starting at a median [interquartile range (IQR)] age of 37.0 [31.0-45.0] years. Overall, median number of 1.8 [0.1-6.9] years passed between HIV diagnosis and the beginning of cART. This time span decreased over time and reached a minimum in 2019 (<1 month). By the end of 2019, 9’462 (96.8%) of patients seen have been on treatment, and in 9’501 (97.2%) individuals viral load (VL) has been below 400 cps/ml.
The SHCS covers 71% of all patients on ART in Switzerland. This estimate is based on a comparison of the Swiss ART sales data from 2017 to 2019 and the prescription data among patients registered in the SHCS. Between 2009 and 2018, the Swiss Federal Office for Public Health (FOPH) reported 5’476 new infections, whereas the SHCS registered in this time period 4’868 (89%). In 2019, the SHCS included 59% of the estimated number of HIV-infected people in Switzerland.
The proportion of AIDS-related death decreased and ranged from 12.8% in 2010 to 0% in 2019. Overall 5’166 (24.8%) of the patients died and 5’863 (28.1%) patients were lost to follow-up. The main reasons for loss to follow-up were that patients did not respond to several invitations (39.8% of patients lost to follow-up) or patients moved abroad (22.7%)
The SHCS stores plasma and peripheral blood mononuclear cells (PBMC) samples in a biobank on a regular basis. Since the beginning of the cohort, over 270’000 plasma samples (>1.2 million aliquots) and over 160’000 PBMCs (>490 000 aliquots) have been stored in the SHCS biobanks.
In conclusion, the SHCS is absolutely amazing, has a fantastic infrastructure with a fantastic team and is simply the greatest cohort worldwide ( personal conclusion Dominique Braun )