Prevalence and proportion by age and sex of chronic health conditions in a large healthcare system.

Background: Disease prevalence and distribution by patient characteristics data are needed to guide "representative" patient enrollment in clinical trials and assess relevance of results to patient populations. Our objective was to describe disease prevalence, and age/sex distribution of patients with common chronic conditions from a large population sample.

Methods: A cross-sectional study of all members of Clalit Health Services, alive on January 1, 2020. Included were 26 chronic diseases, and 21 types of malignancies regarded as active by being diagnosed between January 1, 2018- to January 1, 2020, or by prescription of oncologic treatment medications January 1, 2018 and January 1, 2020.

Results: Data from 4,627,183 individuals, 2,274,349 males and 2,352,834 females from newborn to 110 years. Obesity (19%), hypertension (13%), diabetes mellitus (9%), esophagitis-gastritis (5.5%), thyroid disease (5.3%), asthma (5.1%), ischemic heart disease (4.5%), depression (4.5%), osteoporosis (3.8%), and atopic dermatitis (3.6%) were the ten most prevalent conditions. Proportions of age groups varied between conditions (67% of hypertensives were ≥65 years old, 24% ≥80 years; 73% with ischemic heart disease were ≥65 years, 29% ≥80 years; 59% of diabetics were ≥65 years, 17% ≥80 years; 42% of atrial fibrillation patients were ≥80 years; 40% of heart failure patients were ≥80 years). Proportions of males and females for most conditions paralleled prevalence except proportions of women increased after age 80 for cardiovascular diseases, and for diabetes after age 75. The five most frequent active cancers were breast, prostate, colon/rectal, lymphoma and melanoma. The prevalence of cancers increased with age beginning in the middle-aged groups and peaking at very old ages. Women had lower prevalence of lung cancers and accounted for lower percentages of patients with lung cancers (45 vs 55%) but similar percentages for women and men were seen in the patients with colon and rectal cancer (50.4 vs. 49.6% in women) and lymphoma (50.7 vs. 49.3% in women).

Conclusions: Prevalence of medical conditions and distributions differ by age and sex. This information serves as an example and resource for data needed to describe a "representative" clinical population.