3.1 Study population and characteristics
After applying the eligibility criteria,
the derivation cohort included
8,176 cases of serious GI complications from a total of 2,004,031
patients who used NSAIDs for more than 30 consecutive days and 81,760
matched controls (Fig 1). The prevalence and rate of serious GI
complications were 0.41% and 4.85 per 1000 person-years (95% CI,
4.75–4.96), respectively, in the total derivation cohort. The mean age
was 75.9 years, and 71.6% were female; 1.3% of the development cohort
had a history of GI bleeding or perforation and 27.6% had a history of
GI ulcer without bleeding or perforation (Table 1).
3.2 Model development and
performance
The predictors included in the multivariate analysis are presented in
Table S2. Predictive risk factors included in the final model after
parameter selection were as follows: age, sex, high-dose NSAIDs, type of
NSAIDs, GPA with NSAIDs,
concomitant antithrombotic agents, glucocorticoids, SSRI, history of GI
bleeding or perforation, severe
renal disease, and liver cirrhosis. GPA concomitant with NSAIDs included
only PPI and H2RA. Misoprostol
use did not reach statistical significance due to its infrequent use.
The scores and adjusted OR for each risk factor are shown in Table 2.
The points from -5 to 18 were assigned for each risk factor.
For the prediction of serious GI
complications, the cutoff score for classifying low-risk vs. high-risk
patients was 16 (Youden Index, 0.42; sensitivity, 0.66; specificity,
0.76; Table 4).
Results from the Hosmer–Lemeshow test for the total score calculated
using the risk scores showed an AUROC of 0.78 (95% CI, 0.77–0.79) from
the internal training dataset and 0.77 (95% CI, 0.76–0.78) from the
internal hold-out validation dataset, which considered acceptable
discrimination (Table 3) [17]. The calibration curves of the
internal hold-out validation dataset demonstrated highly accurate
calibration (calibration slope β =1.11), and the risk of GI
complications increased as the prediction scores increased (Fig S1).