Table 3. Multivariate adjusted ORs (95% CIs) for RA risk associated with acarbose and other variables in newly treated DM patients.

Variable	Model 1	Model 2
Anti-diabetic drug users*
Acarbose user
No	1	1
Yes	0.79 (0.61–1.03)*
Low-dose user	–	1.00 (0.72–1.39)
High-dose user	–	0.60 (0.41–0.89)
Sulphonylurea/meglitinide user
No	1	1
Yes	1.07 (0.91–1.25)	1.08 (0.92–1.26)
Metformin user
No	1	1
Yes	1.27 (1.08–1.50)	1.26 (1.06–1.49)
TZD user
No	1	1
Yes	0.96 (0.74–1.25)	0.96 (0.74–1.24)
Insulin user
No	1	1
Yes	0.64 (0.46–0.89)	0.62 (0.45–0.87)
Statin user
No	1	1
Yes	1.14 (0.96–1.35)	1.14 (0.96–1.36)
DM duration, each incremental year	1.22 (1.18–1.26)	1.22 (1.18–1.27)
DM end-organ disease (ICD9-CM: 250.1–9)	2.66 (2.22–3.18)	2.67 (2.23–3.19)
No
Yes
Charlson comorbidity index, each incremental score	1.28 (1.26–1.31)	1.28 (1.26–1.31)
Geographic region
Northern	1	1
Central	0.97 (0.80–1.19)	0.97 (0.79–1.18)
Southern	0.98 (0.82–1.17)	0.98 (0.82–1.17)
Eastern	1.18 (0.74–1.89)	1.18 (0.73–1.88)
Periodontitis
No	1	1
Yes	1.11 (0.91–1.35)	1.11 (0.91–1.35)

Abbreviations: RA, rheumatoid arthritis; DM, diabetes mellitus; TZD, thiazolidinediones; ICD9-CM, International Classification of Diseases, 9th Revision, Clinical Modification. Conditional logistic regression model was used to conduct the analyses, and all variables listed in the table were adjusted. In model 1, acarbose user was categorized as non-user and user. In model 2, acarbose use was further categorized as low- or high-dose based on the median annual cumulative dose (i.e., ≤16,950 mg, >16,950 mg).

^*P = 0.079.