Nested study in the Swiss hepatitis C cohort study (SCCS): to compare the Standardised Mortality Ratios (SMRs) of those in the cohort to the Swiss population

• Forschungsstelle: BAG
• Projektnummer: 07.003843
• Projekttitel Englisch: Nested study in the Swiss hepatitis C cohort study (SCCS): to compare the Standardised Mortality Ratios (SMRs) of those in the cohort to the Swiss population

Schlüsselwörter (Französisch)

• épidémiologie
• hépatite C
• cohorte
• surveillance
• mortalité

Kurzbeschreibung (Französisch)

Dans le cadre de l'ètude suisse de cohorte hépatite C (SCCS), l'OFSP réalise un sous-projet d'analyse épidémiologique visant à comparer les données des patients enrolés dans la cohorte avec celles des patients déclarés à l'OFSP dans le système de surveillance, ainsi qu'à effectuer des analyses complémentaires sur la cohorte permettant de valider, de compléter et d'enrichir l'interprétation des données de surveillance l'OFSP recoit pour cela un soutien du Fonds National de la Recherche scientifique, à l'aide duquel il indemnise l'Institute de médicine sociale et préventive de Berne pour les travaux d'analyse qu'il effectue à sa demande.

Déterminer les ratios de mortalité standardisés (RMS) pour les patients avec hépatite C enrôlés dans la cohorte par rapport aux taux de mortalité spécifiques pour le sexe et l’âge dans la population Suisse en général. Les calculs de RMS seront stratifiés pour différents paramètres (facteur de risque pour l’infection, cirrhose, atteinte hépatique, génotype, co-infections, traitement…).

Projektziele (Französisch)

Données complémentaires importantes par rapport à celles obtenues du système de déclaration obligatoire et de l’Office fédéral des Statistiques : fardeau de la maladie, déterminants de progression de la maladie et implications de santé publique

Abstract (Englisch)

Background/Aims: To describe the excess all-cause mortality of participants in the Swiss Hepatitis C Cohort. Methods: We calculated all-cause standardised mortality ratios (SMR) and 95% confidence intervals (CI) using age, sex and calendar year-specific Swiss all-cause mortality rates. Multivariable Poisson regression was used to model the variability of SMR by cirrhotic stage, genotype (1 versus all others), co-infection with hepatitis B virus or HIV, injection drug use and alcohol intake. Results: 66 deaths were recorded out of 2131 participants. The crude all-cause SMR was 4.0 (95% CI: 3.1 - 5). Being cirrhotic resulted in a crude SMR of 8.4 (95% CI: 6 – 11.7) and co-infection with HIV a crude SMR of 24.5 (95% CI: 14.5 – 41.4). Multivariable analysis showed that cirrhotic patients had an approximately three times higher SMR than non-cirrhotic patients and that the SMR did not vary with HCV genotype (p=0.79). There was no excess mortality if participants were not cirrhotic, not co-infected with hepatitis B or HIV, not injection drug users and were not heavy alcohol consumers. Conclusions: In contrast to findings from other cohort studies, we found that participants infected with genotype 1 did not appear to experience higher excess mortality.

Publikationen / Ergebnisse (Englisch)

Prasad, L., Masserey Spicher, V., Negro, F., Rickenbach, M., Zwahlen, M and the Swiss Hepatitis C Cohort Study Group. Little evidence that hepatitis C virus leads to a higher risk of mortality in the absence of cirrhosis and excess alcohol intake: the Swiss Hepatitis C Cohort Study. J Viral Hepatol (in press)

ABSTRACT

Objective: To describe the all-cause mortality of participants in the Swiss Hepatitis C Cohort compared to the Swiss general population. Design: Cohort study. Setting: Patients with hepatitis C virus (HCV) infection attending secondary and tertiary care centres in Switzerland. Patients: 1645 patients with HCV infection followed up for a mean of over 2 years. Main outcome measures: We calculated all-cause standardised mortality ratios (SMR) and 95% confidence intervals (CI) using age, sex and calendar year-specific Swiss all-cause mortality rates. Multivariable Poisson regression was used to model the variability of SMR by cirrhotic status, HCV genotype, infection with hepatitis B virus or HIV, injection drug use and alcohol intake. Results: 61 deaths were recorded out of 1645 participants. The crude all-cause SMR was 4.5 (95% CI: 3.5 – 5.8). Patients co-infected with HIV had a crude SMR of 20 (95% CI: 11.1 – 36.1). The SMR of 1.1 (95% CI: 0.63 – 2.03) for patients who were not cirrhotic, not infected with HBV or HIV, did not inject drugs, were not heavy alcohol consumers (<=40g/day) and were not genotype 3, indicated no strong evidence of excess mortality. Conclusions: We found little evidence of excess mortality in hepatitis C infected patients who were not cirrhotic, in the absence of selected risk factors. Our findings emphasise the importance of providing appropriate preventive advice, such as counselling to avoid alcohol intake, in those infected with HCV.

Keywords: cirrhosis, hepatitis C virus, standardised mortality ratio, Switzerland.