Background Causes of death and hospitalizations are well studied in developed countries, but studies are lacking in Asian countries. The Department of Rheumatology and Immunology in Singapore General Hospital was founded in March 2003, and sees about 20,000 patients each year.
Objectives The aim of our retrospective study was to look at the causes of mortality and inpatient hospitalizations over 10 years.
Methods We performed a retrospective study of all patients admitted to the department and demised from March 2003 till February 2013. All inpatient hospitalization records were reviewed. Demographics, date and duration of rheumatological diagnosis, date of death, cause of death, laboratory results and comorbidities were recorded.
Results We found a total of 130 patients in our study. 37 (28.5%) had systemic lupus erythematosus, 30 (23.1%) rheumatoid arthritis, 19 (14.6%) inflammatory myositis, 18 (13.8%) vasculitides, 8 (6.2%) systemic sclerosis, 4 (3.1%) primary Sjogren's, 3 (2.3%) catastrophic antiphospholipid syndrome, 3 (2.3%) calcium pyrophosphate disease, and 8 (6.2%) had other diagnoses. 101 patients were female (female:male =3.5:1). Our patients were multiethnic, consisting of Chinese (77.7%), Malays (10.8%), Indians (8.5%) and others (3.1%). Mean age of diagnosis of the rheumatological condition was 55.9 years ±17.6 years. Median number of hospitalizations was 5.5 (range 1-38) per patient over the 10 years. 64.6% of patients had more than 3 hospitalizations per year prior to death. Median disease duration was 2.8 years (range 0-36.0 years) prior to death. 30.0% of the patients had demised within 6 months of diagnosis. Only 9 (0.1%) of the patients defaulted their appointments.
Reasons for hospitalization in order of frequency were: infections (45.4%), worsening renal failure (41.4%), fever (32.3%), arthritis (30.8%), congestive cardiac failure (24.6%), serositis (22.3%), symptomatic interstitial lung disease (20.0%) and cutaneous vasculitis (17.0%). Of all infections, majority were lung infections (89.9%), urinary tract infections (57.6%) and skin and soft tissue infections (32.2%).
Most common comorbidities were related to atherosclerotic disease and traditional cardiovascular risk factors. 54.6% had hypertension, 44.6% hyperlipidemia, 41.5% chronic renal insufficiency, 24.6% diabetes mellitus, 12.3% were smokers, 12.3% had a cerebrovascular event and 6.9% had ischemic heart disease.
Causes of mortality included treatment related infections (36.9%), malignancies (12.3%) and disease-related factors such as cardiovascular involvement (16.2%), interstitial lung disease (10.0%) and gastrointestinal involvement (6.9%).
Majority of patients were on corticosteroids (87.7%), whilst commonly used steroid-sparing agents included hydroxychloroquine (28.5%), azathioprine (22.3%), cyclophosphamide (20%), mycophenolate mofetil (17.7%) and methotrexate (13.8%). Only 21 patients (16.2%) were on biological therapy at the time of demise, 6 on tumour necrosis factor inhibitors and 15 on rituximab. All the patients on cyclophosphamide had developed treatment-related infections.
Conclusions In our cohort, infections were the most common cause of hospitalization and treatment-related infections accounted for the majority of mortalities. Further studies will be needed to determine predictors of mortality, especially in patients that died within 6 months.
Disclosure of Interest None declared