This retrospective nationwide cohort study used administrative claims data from the Korean
National Health Insurance Service (NHIS) and the combined health check-up database of the
National Health Insurance Corporation between 2013 and 2020.
The investigators included patients newly diagnosed with HCMP between January 2015 and
December 2020. Patients aged <20 years, those who were already diagnosed with HCMP before
2015, and those with cancer were excluded from the analysis.
The follow-up period was defined as the time from the index date (date of diagnosis) to each
outcome event, date of death, or end of the study period (December 31, 2020), whichever came
first.
Patients' demographic data, comorbidities, concomitant medications, and income level were
collected from the Korean NHIS database. The recent health check-up data from the index date
was also ascertained, including height, weight, waist circumference, blood pressure, health
surveys, and laboratory exam. Health survey included family history, smoking history, alcohol
history, and the level of individual physical activity.
According to BMI following the World Health Organization recommendation for Asian population,
study patients were categorized into 5 groups: underweight, <18.5 kg/m2; normal range, 18.5
to <23 kg/m2; overweight, 23 to <25 kg/m2; obese I, 25 to <30 kg/m2; and obese II, ≥30
kg/m2[4]. The investigators defined the proportion of medical use by calculating formula with
the recuperation cost and the number of the visit to hospitals.
During the follow-up period, the investigators assessed 3 clinical outcomes, including
all-cause death, cardiovascular hospitalization and the recurrence rate. Clinical outcomes
were mainly defined by the the International Classification of Diseases, 10th revision
(ICD-10). Patients were censored at the clinical outcomes or the end of the study period
(December 31, 2020), whichever came first.
All categorical variables are presented as frequencies and percentages. Normally distributed
data were presented as mean ± standard deviation, whereas nonparametric data are presented as
median and interquartile range by BMI.
Cox proportional hazard regression analyses were performed to identify the association of BMI
with the primary and secondary outcomes, calculating hazard ratio (HR) and 95% confidence
interval (CI) and adjusting for the following potential confounders: sex, age, systolic blood
pressure, fasting glucose level, total cholesterol level, alcohol consumption, smoking
status, physical activity, household income, use of antihypertensive agents, use of statins,
use of antiplatelet agents, previous history of MI, previous history of stroke, and index
year. All analyses were conducted using R-statistics.