An unbiased theoretical estimator for the case fatality rate

Introduction:Case fatality rates (CFRs) and case recovery rates (CRRs) are frequently used to define health consequences related to specific disease epidemics, including the COVID-19 pandemic. This study aimed to compare various methods and models for calculating CFR and CRR related to COVID-19 based on the global and national data available as of April 2020.Methods:This analytical epidemiologic study was conducted based on detailed data from 210 countries and territories worldwide in April 2020. We used three different formulas to measure CFR and CRR, considering all possible scenarios.Results:We included information for 72 countries with more than 1,000 cases of COVID-19. Overall, using first, second, and third estimation models, the CFR were 6.22%, 21.20%, and 8.67%, respectively; similarly, the CRR was estimated as 23.21%, 78.86%, 32.23%, respectively. We have shown that CFRs vary so much spatially and depend on the estimation method and timing of case reports, likely resulting in overestimation.Conclusions:Even with the more precise method of CFRs estimation, the value is overestimated. Case fatality and recovery rates should not be the only measures used to evaluate disease severity, and the better assessment measures need to be developed as indicators of countries’ performance during COVID-19 pandemic.

A systematic review and meta-analysis of published research data on COVID-19 infection fatality rates

RTAS—Case fatality rate, crash injury rate and motor vehicles: Time trends between a developed and developing country

The Higher COVID-19 Fatality Rate Among Kidney Transplant Recipients Calls for Further Action.

Stroke mortality varies greatly from country to country. In 1985, the highest figures in eastern European countries were 6- to 7-fold those of countries with the lowest mortality rates,1 and the same trend has continued in the 1990s.2 The mortality rates have not, however, remained stable during the last decades. In most countries, a significant reduction has occurred, whereas in some countries the opposite is true: during 1970 to 1985, the annual changes ranged from +3.9% to −7.1%, and during 1985 to 1994, from +3.2% to −6.8%.1,2 The obvious causes of the reduced mortality rates have been either a decreased incidence of stroke or the case-fatality rate, or both. The explanations for the growing mortality rates, mainly in the eastern European countries, have been more or less speculative. In the present study, Sarti and associates have answered these questions. Their impressive patient material consisted of 36 000 young (35 to 64 years) …

We analyzed state-specific stroke-hospitalization, case-fatality, and mortality rates for the US Medicare population for 1989, using national data resources of the Health Care Financing Administration (HCFA), the National Center for Health Statistics, and the Bureau of the Census. State-specific hospital admission rates for stroke ranged from 0.66 to 1.26%, compared with the national value of 0.94%. Both hospital-usage rates and deviations of observed rates from predicted values (based on statistical models of the HCFA) showed significant spatial autocorrelation, with high rates clustered in the southeastern United States and low rates clustered in the Mountain census division of the West and also somewhat in the Northeast. Case-fatality rates increased nationally from 14.9% at 15 days after hospital admission to 31.2% at 180 days after hospital admission. State-level case-fatality rates showed relatively little interstate variation and no clear or consistent spatial pattern, although there was statistically significant spatial autocorrelation at several intervals after hospital admission. Admission rates and case-fatality rates were not significantly associated at any interval after admission to 180 days, suggesting that variation in case-fatality rates was not simply a result of differences in severity-of-illness thresholds for hospital admission. State-specific stroke-mortality rates ranged from 294.5 to 523.5 per 100,000 population, compared with the national value of 415.3 per 100,000 population. State-specific mortality rates for stroke showed significant spatial autocorrelation, with high rates clustered in the South and low rates clustered in the Northeast and the Mountain census division of the West. The spatial distribution of stroke-mortality rates strongly resembled the spatial distribution of hospitalization rates but did not resemble the spatial distribution of case-fatality rates at any interval from 15 to 180 days after hospital admission. Indeed, in univariate spatial-regression models fitted to the data using a maximum likelihood procedure and weighted for non-constant variances, the best predictor of state-level stroke-mortality rates was the hospital-utilization rate for stroke; attempts to improve the model by including case fatality at various intervals and interaction terms did not yield a significant improvement. These data suggest that factors determining stroke occurrence and hospital utilization are more important than factors determining case fatality in terms of explaining the long-standing distribution of stroke mortality in the United States. Factors affecting only case fatality but not hospitalization, such as the quality of medical care provided in the hospital, cannot explain the geographic distribution of stroke mortality in the United States.

BackgroundThe case fatality ratio (CFR), the ratio of deaths from an infectious disease to the number of cases, provides an assessment of virulence. Calculation of the ratio of the cumulative number of deaths to cases during the course of an epidemic tends to result in a biased CFR. The present study develops a simple method to obtain an unbiased estimate of confirmed CFR (cCFR), using only the confirmed cases as the denominator, at an early stage of epidemic, even when there have been only a few deaths.Methodology/Principal FindingsOur method adjusts the biased cCFR by a factor of underestimation which is informed by the time from symptom onset to death. We first examine the approach by analyzing an outbreak of severe acute respiratory syndrome in Hong Kong (2003) with known unbiased cCFR estimate, and then investigate published epidemiological datasets of novel swine-origin influenza A (H1N1) virus infection in the USA and Canada (2009). Because observation of a few deaths alone does not permit estimating the distribution of the time from onset to death, the uncertainty is addressed by means of sensitivity analysis. The maximum likelihood estimate of the unbiased cCFR for influenza may lie in the range of 0.16–4.48% within the assumed parameter space for a factor of underestimation. The estimates for influenza suggest that the virulence is comparable to the early estimate in Mexico. Even when there have been no deaths, our model permits estimating a conservative upper bound of the cCFR.ConclusionsAlthough one has to keep in mind that the cCFR for an entire population is vulnerable to its variations among sub-populations and underdiagnosis, our method is useful for assessing virulence at the early stage of an epidemic and for informing policy makers and the public.

People with advanced CKD are at high risk of mortality and morbidity from coronavirus disease 2019 (COVID-19). We measured rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe outcomes in a large population attending advanced CKD clinics during the first 21 months of the pandemic. We examined risk factors for infection and case fatality, and we assessed vaccine effectiveness in this population. In this retrospective cohort study, we analyzed data on demographics, diagnosed SARS-CoV-2 infection rates, outcomes, and associated risk factors, including vaccine effectiveness, for people attending a province-wide network of advanced CKD clinics during the first four waves of the pandemic in Ontario, Canada. In a population of 20,235 patients with advanced CKD, 607 were diagnosed with SARS-CoV-2 infection over 21 months. The case fatality rate at 30 days was 19% overall but declined from 29% in the first wave to 14% in the fourth. Hospitalization and intensive care unit (ICU) admission rates were 41% and 12%, respectively, and 4% started long-term dialysis within 90 days. Significant risk factors for diagnosed infection on multivariable analysis included lower eGFR, higher Charlson Comorbidity Index, attending advanced CKD clinics for more than 2 years, non-White ethnicity, lower income, living in the Greater Toronto Area, and long-term care home residency. Being doubly vaccinated was associated with lower 30-day case fatality rate (odds ratio [OR], 0.11; 95% confidence interval [CI], 0.03 to 0.52). Older age (OR, 1.06 per year; 95% CI, 1.04 to 1.08) and higher Charlson Comorbidity Index (OR, 1.11 per unit; 95% CI, 1.01 to 1.23) were associated with higher 30-day case fatality rate. People attending advanced CKD clinics and diagnosed with SARS-CoV-2 infection in the first 21 months of the pandemic had high case fatality and hospitalization rates. Fatality rates were significantly lower in those who were doubly vaccinated. This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_04_10_CJN10560922.mp3.

BackgroundEbola and Marburg virus diseases are said to occur at a low prevalence, but are very severe diseases with high lethalities. The fatality rates reported in different outbreaks ranged from 24–100%. In addition, sero-surveys conducted have shown different seropositivity for both Ebola and Marburg viruses. We aimed to use a meta-analysis approach to estimate the case fatality and seroprevalence rates of these filoviruses, providing vital information for epidemic response and preparedness in countries affected by these diseases.MethodsPublished literature was retrieved through a search of databases. Articles were included if they reported number of deaths, cases, and seropositivity. We further cross-referenced with ministries of health, WHO and CDC databases. The effect size was proportion represented by case fatality rate (CFR) and seroprevalence. Analysis was done using the metaprop command in STATA.ResultsThe weighted average CFR of Ebola virus disease was estimated to be 65.0% [95% CI (54.0–76.0%), I2 = 97.98%] whereas that of Marburg virus disease was 53.8% (26.5–80.0%, I2 = 88.6%). The overall seroprevalence of Ebola virus was 8.0% (5.0%–11.0%, I2 = 98.7%), whereas that for Marburg virus was 1.2% (0.5–2.0%, I2 = 94.8%). The most severe species of ebolavirus was Zaire ebolavirus while Bundibugyo Ebolavirus was the least severe.ConclusionsThe pooled CFR and seroprevalence for Ebola and Marburg viruses were found to be lower than usually reported, with species differences despite high heterogeneity between studies. Countries with an improved health surveillance and epidemic response have lower CFR, thereby indicating need for improving early detection and epidemic response in filovirus outbreaks.

In December 2019, SARS COV-2 which originated in the Chinese city of Wuhan achieved pandemic proportions and spread rapidly to countries through International air traffic causing acute respiratory infection and deaths. Presence of International airports, demography, health financing and human developments factors were assumed to influence COVID-19 cases burden and case fatality rate (CFR). So, this study was undertaken to find a association between these factors and COVID-19 cases and deaths. The study used 48 districts using purposive sampling as proxy for cities and used secondary data analysis. Data was obtained for various variables like demographic, Health Financing, Indices and Testing infrastructure, COVID cases burden and case fatality from trusted sources. Descriptive statistics correlational statistics using Pearsons coefficient students T was used to describe, correlate and find significant difference in the data. The analysis found a significant difference between COVID cases burden in districts with International Airports (p<0.039) and those without it. Positive correlation of population density (r=0.65) with COVID-19 case burden and negative correlation of case fatality rate with NITI Aayogs health index (r=-0.12), human development index (HDI) (r=-0.18), per-capita expenditure on health (r=-0.072) and a correlation of r=0.16 was observed for gross state domestic product. Decongestion of cities through perspective urban planning is the need of the hour. Stricter quarantine measures in those districts with international airports can help reduce the transmission. Negative correlation of HDI and NITI Aayogs health index with CFR emphasizes the importance of improvements in social determinants of health.

Background: The new Coronavirus disease (COVID-19) was first identified in China in 2019. Case fatality rate (CFR) indicator of the disease is one of the most important indices noticed by experts, policymakers, and managers, based on which daily evaluations and many judgments are made. CFR can change during epidemics. This study aimed to estimate the actual number of COVID-19 cases in Iran and to calculate the early CFR for the disease based on official statistics. Methods: This was a descriptive study whose data were obtained from the website of the Ministry of Health and Medical Education of Iran from February 20, 2020 until March 26, 2020. CFR has been obtained by dividing the total number of deaths by the total number of confirmed cases at one point in time. In this study, the actual number of COVID-19 cases in Iran was estimated based on the mortality model in 4 scenarios. Excel 2013 software was used to analyze the data. Results: According to the findings of this study, In Iran, until March 26, 2020, a total of 27 017 people have been infected by COVID-19 and 2077 died of it. However, CFR indicator had a descending trend in Iran: 100%, 18.6%, 8.8%, 3.3%, 6.9%, and 7.7% on days 1, 5, 10, 20, 30, and 35, respectively. The actual number of COVID-19 cases in Iran was estimated to be 4 789 454, 2 873 673, 1 436 836, and 718418 as of March 26, 2020 according to the 4 scenarios, respectively. Conclusion: In emerging epidemics, CFR indicator must not be used as a basis to judge the performance of a health system unless that epidemic condition has been clarified. Moreover, it is suggested that in the outbreak of an epidemic, specifically emerging diseases, CFR must not be the base of judgment. Making judgments, specifically in the outbreak of emerging epidemics, based on fatality rate can lead to information bias. It is also possible to estimate the total number of patients based on the CFR in circumstances where little information is available on the disease.

Nosocomial pneumonia (NP) and ventilator associated pneumonia (VAP) have been associated with financially significant economic burden and increased case fatality rate in adult intensive care units (ICUs). This study was designed to evaluate case fatality rate among patients with NP and VAP in a respiratory ICU. In 2008-2013, VAP and NP in the ICUs were included in this retrospective single-centre cohort study. Data on demographics, co-morbidities, severity of illness, mechanical ventilation, empirical treatment, length of hospital stay and laboratory findings were recorded in each group, as were case fatality rate during ICU admission and after discharge including short-term (28-day) and long-term (a year) case fatality rate. A total of 108 patients with VAP (n = 64, median (IQR) age: 70 (61-75) years, 67.2% were men) or NP (n = 44, median (IQR) age: 68 (62-74) years, 68.2% were men) were found. Appropriate empirical antibiotic therapy was identified only in 45.2 and 42.9% of patients with VAP and NP, respectively. Overall case fatality rate in VAP and NP (81.3 vs 84.1), ICU case fatality rate (42.2 vs 45.5%), short-term case fatality rate (15.6 vs 27.3%) and long-term case fatality rate (23.4 vs 11.4%) were similar between VAP and NP groups along with occurrence 50% of case fatality rate cases in the first 2 months and 90% within the first year of discharge. Multivariate analysis showed that chronic obstructive pulmonary disease (COPD) (HR: 3.15, 95% CI: 1.06-9.38; p = 0.039) and presence of septic shock (HR: 3.83, 95% CI: 1.26-11.60; p = 0.018) were independently associated with lower survival. In conclusion, our findings in a retrospective cohort of respiratory ICU patients with VAP or NP revealed high ICU, short- and long-term case fatality rates within 1 year of diagnosis, regardless of the diagnosis of NP after 48 h of initial admission or after induction of ventilator support. COPD and presence of septic shock are associated with high fatality rate and our findings speculate that as increasing compliance with infection control programs and close monitoring especially in 2 months of discharge might reduce high-case fatality rate in patients with VAP and NP.

Objective To report trends in event and case fatality rates for acute myocardial infarction and examine the relative contributions of changes in these rates to changes in total mortality from...

Objective: To present the epidemiological characteristics of ≤28 days case fatality in both hemorrhagic stroke (HS) and ischemic stroke (IS) patients in national cardiovascular disease surveillance areas from 2015 to 2019. Methods: Data on all new patients with stroke and ≤28 days outcomes from 2015 to 2019 were from the China Registry of Cardiovascular Events, which was established in 2014, covering 100 counties (cities, districts) in 31 provinces in China. Poisson regression was used to analyze the annual trend of ≤28 days case fatality. The age-standardized case fatality was directly calculated based on all new stroke onset. Results: In total, 112 069 deaths in HS patients ≤28 days after the onset, as well as 94 373 in IS patients, were identified during the study period. In 2019, the ≤28 days case fatality rate in HS patients was 4.75 times that of IS patients (37.08% vs. 7.80%), as well as that 4.06 times in urban areas (30.13% vs. 7.43%) and 5.30 times in rural areas (42.63% vs. 8.05%), respectively. Thus, in rural areas, HS patients showed 41.49% higher ≤28 days case fatality rate than that in urban areas, as well as 8.34% higher in IS patients. Those ≤28 days case fatality in both stroke subtypes onset increased with age and reached the highest level in those aged 85 years and over. During the study period, HS and IS patients in each age group displayed significant decrease trend in ≤28 days case fatality rate (trend P<0.001). Compared with that in 2015, the age-standardized ≤28 days case-fatality in HS patients in 2019 decreased by 28.52%, which was more in urban areas (-34.27%) than that in rural areas (-23.19%). Meanwhile, IS patients experienced a 39.90% reduction in ≤28 days case fatality, which was much lower in urban areas (-31.62%) than in rural areas (-45.10%, all trend P<0.001). Conclusions: From 2015 to 2019, ≤28 days case fatality in both HS and IS patients decreased in China. Wide variations of ≤28 days case-fatality were evident in the level and trend in stroke subtype, age of patients, as well as urban and rural areas. More precise and comprehensive strategies for stroke prevention, treatment, and post-stroke management are urgently required in China.

Case fatality rates (CFRs) are often used as the key indicator for the measurement of quality of care at hospitals. We examine the trends of obstetric CFRs and very early neonatal mortality rates at hospitals in selected districts of Indonesia after implementation of a facility-based maternal and neonatal health intervention-the Expanding Maternal and Neonatal Survival (EMAS) program. Random-effects Poisson regression models were fitted to routine facility data collected from 101 hospitals over approximately 4years. Predicted incidence rates from the models were used for ascertaining the changes in CFRs and very early neonatal mortality rates during the EMAS intervention period. The obstetric CFR from any maternal complications decreased significantly by 50% (adjusted incidence rate ratio [IRR] 0.50; 95% confidence interval [CI] 0.42-0.61) at hospitals after the implementation of the EMAS program. On average, the CFR decreased from 5.4 to 2.6 deaths per 1000 cases of obstetric complications admitted during the program period. The very early neonatal mortality rate (deaths within 24hours of birth) decreased by 21% (IRR 0.79; 95% CI, 0.65-0.96). Our study suggests that overall obstetric case fatality and very early neonatal mortality rates-two indicators for tracking the quality of emergency obstetric care-decreased significantly at hospitals after the implementation of the EMAS intervention program in Indonesia.