Estimating mortality in rare diseases using a population-based registry, 2002 through 2019

Area of Science:

• Epidemiology
• Public Health
• Rare Diseases

Background:

• Rare diseases (RD) are complex and heterogeneous, with variable prognoses.
• Real-world data on the overall mortality and survival of RD patients are limited.
• Population-based registries offer valuable insights into RD epidemiology.

Purpose of the Study:

• To provide population-based data on mortality and survival for a substantial group of rare diseases.
• To analyze mortality ratios and survival rates in RD patients compared to the general population.
• To identify variations in outcomes based on gender, age, and specific disease groups.

Main Methods:

• Utilized a population-based registry covering the Veneto region, Italy (4.9 million inhabitants).
• Analyzed mortality data, including standardized mortality ratios (SMR) and survival rates over a 15-year period.
• Calculated SMR with 95% confidence intervals, stratified by gender.

Main Results:

• A total of 3367 deaths occurred during the study period, predominantly in males, elderly patients, and those with low-prevalence diseases.
• RD patients exhibited a significantly higher mortality ratio (SMR = 1.93) compared to the general population, with higher rates in females (2.01) than males (1.86).
• Lowest survival rates were observed in rare neurologic diseases (58%), rare skin diseases (68%), and rare systemic/rheumatologic diseases (81%) after 15 years; only 18% of motor neuron disease patients survived.

Conclusions:

• RD patients experience higher mortality and reduced survival rates globally compared to the general population.
• Significant variations in mortality and survival exist across different rare disease groups, genders, and age demographics.
• Despite advancements, disparities in outcomes for rare diseases persist, necessitating further research and targeted interventions.