Risk stratification model for in-hospital death in patients undergoing percutaneous coronary intervention: a nationwide retrospective cohort study in Japan

Abstract

Objectives: To provide an accurate adjustment for mortality in a benchmark, developing a risk prediction model from its own dataset is mandatory. We aimed to develop and validate a risk model predicting in-hospital mortality in a broad spectrum of Japanese patients after percutaneous coronary intervention (PCI).

Design: A retrospective cohort study was conducted.

Setting: The Japanese-PCI (J-PCI) registry includes a nationally representative retrospective sample of patients who underwent PCI and covers approximately 88% of all PCIs in Japan.

Participants: Overall, 669 181 patients who underwent PCI between January 2014 and December 2016 in 1018 institutes.

Main outcome measures: In-hospital death.

Results: The study population (n=669 181; mean (SD) age, 70.1(11.0) years; women, 24.0%) was divided into two groups: 50% of the sample was used for model derivation (n=334 591), while the remaining 50% was used for model validation (n=334 590). Using the derivation cohort, both 'full' and 'preprocedure' risk models were developed using logistic regression analysis. Using the validation cohort, the developed risk models were internally validated. The in-hospital mortality rate was 0.7%. The preprocedure model included age, sex, clinical presentation, previous PCI, previous coronary artery bypass grafting, hypertension, dyslipidaemia, smoking, renal dysfunction, dialysis, peripheral vascular disease, previous heart failure and cardiogenic shock. Angiographic information, such as the number of diseased vessel and location of the target lesion, was also included in the full model. Both models performed well in the entire validation cohort (C-indexes: 0.929 and 0.926 for full and preprocedure models, respectively) and among prespecified subgroups with good calibration, although both models underestimated the risk of mortality in high-risk patients with the elective procedure.

Conclusions: These simple models from a nationwide J-PCI registry, which is easily applicable in clinical practice and readily available directly at the patients' presentation, are valid tools for preprocedural risk stratification of patients undergoing PCI in contemporary Japanese practice.

Keywords: In-hospital mortality; percutaneous coronary intervention; risk model.

Figure 1

Study cohort creation. PCI, percutaneous coronary intervention; J-PCI, Japanese-PCI.

Figure 2

Integer score and its calibration performance. The agreements between the observed and expected risks of mortality with the developed integer score were assessed across five groups of the total points in the validation cohort. CABG, coronary artery bypass grafting; NSTEMI, non-ST-elevation myocardial infarction; PCI, percutaneous coronary intervention; STEMI, ST-elevation myocardial infarction.