Objective.: To analyze the trend of prevalence and incidence rates for psoriatic arthritis (PsA) and psoriasis in Taiwan, and to determine the changes in medication patterns.Methods.: Data were collected from the Taiwan National Health Insurance Research Database, which covered at least 95% of the population from 2000 to 2013. International Classification of Diseases, 9th edition (ICD-9) was used to identify PsA (ICD-9 696.0) and other psoriasis (ICD-9 696.1). Medications were identified by Anatomical Therapeutic Chemical Classification code. We calculated the annual age standardized prevalence and incidence rate of PsA and psoriasis in individuals aged ≥ 16 years from 2000 to 2013, and used the Poisson regression to test the trends by Wald chi-square statistic.Results.: The prevalence (per 100,000 population) of psoriatic diseases between 2000 and 2013 increased from 11.12 to 37.75 for PsA, and from 179.2 to 281.5 for psoriasis. The incidence (per 100,000 person-yrs) increased from 3.64 to 6.91 in PsA, while there was no significant change in psoriasis. Prevalence and incidence in PsA were more rapidly increased than in psoriasis. Sex ratio (men to women) of PsA decreased from 2.0 to 1.5 in 2000 and 2013, respectively. There was an increase in the use of disease-modifying antirheumatic drugs (DMARD), especially biologics, which is significantly different from topical therapies.Conclusion.: The prevalence and incidence rates of psoriatic disease, especially PsA, were increasing in Taiwan. The medication pattern showed an increase in DMARD and biologics, while use of topical therapies decreased.

Rheumatoid arthritis (RA) is a systemic inflammatory disease with different etiologies in different areas. Our study focused on the prevalence of RA in Taiwan from 2001 to 2011. This study contained longitudinal enrollment files, claims data, catastrophic illness files, and treatment registries from Taiwan Longitudinal Health Insurance Research Database. We identified RA patients by ICD-9-CM code 714.0. The demographical variables including age, sex, income and area of registration were evaluated. The multivariate Poisson regression was applied to calculate relative risk for developing RA. In Taiwan, the ratio of female to male was about 5:1. From 2001 to 2011, significant increasing prevalence of RA, from 0.07% to 0.14%, was found in women. The prevalence of RA was increasing 6% per year in both sex groups. The annual incidence rate (per 10,000 person years) ranged from 1.62 to 2.02 (female: 2.30–3.14; male: 0.71–1.17) from 2003 to 2011. City area had lowest incidence rate of RA compared with suburban or rural area. Higher incidence of RA was observed among lower socioeconomic status. The prevalence of RA was rising from 0.07% in 2001 to 0.14% in 2011. Incidence was about 2/10,000 person-years and female to male ratio was 5:1. Lower socioeconomic status and living rural region might be a risk factor for developing RA.

The aim of the study is to assess the effects of celecoxib and sulfasalazine on the risk of coronary artery disease (CAD) in patients with ankylosing spondylitis (AS). Using the claims data of Taiwan National Health Insurance (NHI) database, a nationally representative data that contain the medical records of 23 million Taiwan residents, we randomly selected 1 million cohort from the database, and then we enrolled only patients who were newly diagnosed with AS (n = 4829) between year 2001 and 2010, excluding patients who had CAD (ICD-9- CM codes: 410–414) before the diagnosis of AS (n = 4112). According to propensity score matched 1:2 on age, gender, AS duration, Charlson comorbidity index, hypertension, and hyperlipidemia, 236 and 472 patients were included in the case (AS with CAD) and control (AS without CAD) groups, respectively. We used the WHO defined daily dose (DDD) as a tool to assess the dosage of sulfasalazine and celecoxib exposure. Conditional logistic regression was used to estimate the crude and adjusted odds ratios (ORs) and 95% confidence interval (CI) for the risk of CAD associated with use of sulfasalazine and celecoxib. Among 4112 AS patients, 8.4% (346/4112) developed CAD. CAD in AS patients were positively associated with age of 35 to 65, Charlson comorbidities index (CCI), hypertension, and hyperlipidemia. There was no gender difference between case and control groups. After adjustment for age, gender, CCI, hypertension, and hyperlipidemia, sulfasalazine users with an average daily dose ≥ 0.5 DDD (0.5 gm/day) had negative association with CAD events as compared to sulfasalazine nonusers (OR 0.63; 95% CI, 0.40–0.99, P < 0.05). NSAIDs, including celecoxib, etoricoxib, but no naproxen and diclofenac were negatively associated with CAD. Celecoxib users, with an average daily dose > 1.5 DDD, were negatively associated with CAD events, compared to celecoxib nonusers (OR 0.34; 95% CI, 0.13–0.89; P < 0.05). In this 10-year population-based case-control study, 8.4% of AS patients developed CAD. Sulfasalazine usage at an average dose of ≥ 0.5 gm/day demonstrated negative association with CAD events in patients with AS.

Objectives: A previous study suggested that colchicine may cause leukopenia and increase the risk of infection, such as pneumonia. Thus, we investigated the potential relationship between colchicine use and risk of developing pneumonia. Methods: Data were collected from Taiwan’s National Health Insurance Research Database (NHIRD), a nationwide, population-based database. A 13-year retrospective cohort study was conducted, and all investigated subjects were identified by International Classification of Disease, Ninth Revision, Clinical Modification, codes between 2000 and 2012. Propensity score matching was applied to adjust for potential confounding variables, and then Cox proportional hazard model was used to evaluate the hazard ratio (HR) of pneumonia in gout patients and its associations with colchicine use, colchicine dosage, and days of colchicine use. Results: A total of 24,410 gout patients were enrolled in this study, including 12,205 cases who were treated with colchicine (colchicine group) and 12,205 cases who did not receive colchicine (non-colchicine group). The overall incidence rates of pneumonia in the colchicine group and non-colchicine group were 18.6 and 12.6 per 1,000 person-years, respectively. The colchicine group had a higher risk of pneumonia as compared with the non-colchicine group [adjusted HR, 1.42; 95% confidence interval (CI), 1.32 to 1.53; P < 0.05]. High cumulative dose and days of colchicine use notably increased the risk of contracting pneumonia. Conclusion: This nationwide population-based cohort study reveals that gout patients taking colchicine are at increased risk of developing pneumonia compared with gout patients who do not use colchicine. Therefore, it is crucial that gout patients being treated with colchicine be given the minimally effective dosage for the shortest possible duration to minimize their risk of pneumonia.