Correlation of population mortality of COVID-19 and testing coverage: a comparison among 36 OECD countries and Taiwan

Although testing is widely regarded as critical to fighting the Covid-19 pandemic, what measure and level of testing best reflects successful infection control remains unresolved. Our aim was to compare the sensitivity of two testing metrics-population testing number and testing coverage-to population mortality outcomes and identify a benchmark for testing adequacy with respect to population mortality and capture of potential disease burden. This ecological study aggregated publicly available data through April 12 on testing and outcomes related to COVID-19 across 36 OECD (Organization for Economic Development) countries and Taiwan. All OECD countries and Taiwan were included in this population-based study as a proxy for countries with highly developed economic and healthcare infrastructure. Spearman correlation coefficients were calculated between the aforementioned metrics and following outcome measures: deaths per 1 million people, case fatality rate, and case proportion of critical illness. Fractional polynomials were used to generate scatter plots to model the relationship between the testing metrics and outcomes. Testing coverage, but not population testing number, was highly correlated with population mortality (rs= -0.79, P=5.975e-09 vs rs = - 0.3, P=0.05) and case fatality rate (rs= -0.67, P=9.067e-06 vs rs= -0.21, P=0.20). A testing coverage threshold of 15-45 signified adequate testing: below 15, testing coverage was associated with exponentially increasing population mortality, whereas above 45, increased testing did not yield significant incremental mortality benefit. Testing coverage was better than population testing number in explaining country performance and can be used as an early and sensitive indicator of testing adequacy and disease burden. This may be particularly useful as countries consider re-opening their economies.

Risk of hepatocellular carcinoma and habits of alcohol drinking, betel quid chewing and cigarette smoking: a cohort of 2416 HBsAg-seropositive and 9421 HBsAg-seronegative male residents in Taiwan.

OBJECTIVES: Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC) in the world. The specific aim of this study is to assess the associations between the risk of HCC and habits of alcohol drinking, betel quid chewing and cigarette smoking among subjects with and without chronic HBV infection. METHODS: A total of 11,837 male residents in Taiwan were recruited in this community-based cohort study. Hepatitis B surface antigen (HBsAg) and antibody against hepatitis C virus (anti-HCV) in serum were determined by enzyme immunoassay, and the habits of alcohol drinking, betel quid chewing and cigarette smoking were collected through standardized personal interview according to a structured questionnaire. During the follow-up period of 91,885 person-years, 115 incident HCC cases were identified through data linkage with national cancer registry profile. The relative risk (RR) of developing HCC for habits of various substance use and chronic HBV infection were estimated by Cox's proportional hazards regression analyses. RESULTS: Significantly increased HCC risk was observed for seropositives of HBsAg or anti-HCV, alcohol drinkers, betel quid chewers and cigarette smokers. There was a significant dose-response relationship between the risk of HCC and the number of habits of substance use. The highest multivariate-adjusted HCC risk was observed among HBsAg-seropositive substance users (RRs: 17.9-26.9), followed by HBsAg-seropositive non-users (RRs: 13.1-19.2), HBsAg-seronegative substance users (RRs: 1.6-2.7) and HBsAg-seronegative non-users (referent with RR = 1). The multivariate-adjusted relative HCC risks for habits of use of various substances were more profound among HBsAg-seronegatives than HBsAg-seropositive ones. CONCLUSION: Habitual alcohol drinking, betel quid chewing and cigarette smoking are associated with an increased risk of HCC. Abstinence from substance use is important for the prevention of HCC in areas where chronic HBV infection is endemic.