Comorbidity in multiple sclerosis: its temporal relationships with disease onset and dose effect on mortality.

BACKGROUND AND PURPOSE: We aimed to determine the burden of comorbidities at the time of diagnosis of multiple sclerosis (MS), the risk of developing new comorbidities after diagnosis and the effect of comorbidities on mortality in patients with MS. METHODS: This study used data from 2526 patients with incident MS and 9980 age-, sex- and physician-matched controls without MS identified from the UK Clinical Practice Research Datalink. RESULTS: Before the MS diagnosis, the adjusted odds ratio for the association between MS and a Charlson comorbidity index score of 1-2, 3-4 or ≥5 was 131 [95% confidence interval (CI), 1.17-1.47], 1.65 (95% CI, 1.20-2.26) or 3.26 (95% CI, 1.58-6.70), respectively. MS was associated with increased risks of cardiovascular and neurological/mental diseases. After diagnosis, the adjusted hazard ratio for the association between MS and an increased risk of developing comorbidities was 1.13 (95% CI, 1.00-1.29). The risk of developing any comorbidity in terms of neoplasms, musculoskeletal/connective tissue diseases or neurological/mental diseases was higher in MS. Patients with MS had a higher mortality risk compared with controls, with a hazard ratio of 2.29 (95% CI, 1.81-2.73) after adjusting for comorbidities. There was a dose effect of pre-existing comorbidities on mortality. CONCLUSIONS: Patients with MS have an increased risk of developing multiple comorbidities both before and after diagnosis and pre-existing comorbidities have an impact on survival.

Epilepsy and associated mortality in patients with multiple sclerosis.

BACKGROUND AND PURPOSE: We aimed to determine the prevalence of epilepsy in patients with multiple sclerosis (MS) at diagnosis, the risk of developing epilepsy after the diagnosis of MS and the relative risk of mortality associated with epilepsy. METHODS: We used the UK Clinical Practice Research Data-link to identify 2526 patients with incident MS and 9980 age-, sex- and index year-matched non-MS controls from 1997 to 2006. Logistic regression was used to estimate odds ratios [95% confidence interval (CI)] for epilepsy and Cox regression was used to estimate hazard ratios (HRs) (95% CI) for epilepsy and mortality. RESULTS: Patients with incident MS were on average 45 years old and 70.9% were female. At diagnosis, the prevalence of epilepsy in patients with MS was 1.30% compared with 0.57% in non-MS controls. At diagnosis, MS was associated with an adjusted odds ratio (95% CI) of 2.11 (1.36-3.27) for pre-existing epilepsy. Among epilepsy-free patients, the cumulative probabilities of developing epilepsy, first recorded within 10 years of the index date, were 2.77% for patients with MS and 0.90% for controls. MS was associated with an adjusted HR (95% CI) of 6.01 (2.94-12.29) for epilepsy. Among patients with MS, epilepsy was associated with an HR (95% CI) of 2.23 (1.02-4.84) for all-cause mortality. CONCLUSIONS: This population-based study found an increased prevalence of epilepsy in patients with MS at diagnosis when compared with non-MS controls and the risk of developing epilepsy was also higher following the MS diagnosis. Patients with MS with epilepsy had a higher risk of mortality compared with those without.

Cancer risk among patients with systemic sclerosis: a nationwide population study in Taiwan.

OBJECTIVES: Systemic sclerosis (SSc) has been associated with high cancer risk. We compared the cancer risk among SSc patients with that among the general Taiwanese population. METHODS: The catastrophic illness registry of the Taiwan National Health Insurance Research Dataset (NHIRD) was used to identify patients diagnosed with SSc and cancer in Taiwan during 1996-2008. The standardized incidence ratio (SIR) for cancer was calculated, and mortality was ascertained using the data from the National Death Registry. RESULTS: Data analysis revealed that 2053 (472 men, 1581 women) Taiwanese individuals were diagnosed with SSc during the study period and 83 (30 men, 53 women) had cancer. The incidence of cancer was 6.9/1000 person-years. The most common cancer sites in male SSc patients were the lung (n = 10), oral cavity and pharynx (n = 8), and gastrointestinal tract (n = 4), and those in female patients were the breast (n = 11), lungs (n = 11), and blood (n = 6). Compared to the Taiwanese population of 1996, the all-cancer SIR for SSc was 1.63 [95% confidence interval (CI) 1.31-2.01]. Cancer risk was elevated for cancers of the lung (SIR 4.20), oral cavity and pharynx (SIR 3.67), and blood (SIR 3.50). A cancer diagnosis in SSc patients was associated with a hazard ratio (HR) of 2.15 (95% CI 1.30-3.53). Among cancer patients, a diagnosis of SSc was not associated with increased mortality. CONCLUSIONS: SSc patients are at high risk of developing cancer, especially of the lung, oral cavity and pharynx, and blood.

Incidence, cancer risk and mortality of dermatomyositis and polymyositis in Taiwan: a nationwide population study.

BACKGROUND: Nationwide data on the epidemiology of dermatomyositis (DM) and polymyositis (PM) were limited. OBJECTIVES: This study was to estimate the incidence, occurrence of cancer and mortality of DM and PM in Taiwan. METHODS: Both the register of critical illness of the Taiwan National Health Insurance Research Dataset and the National Death Registry of Taiwan were used to calculate estimates of the incidence, cancer association, and mortality of DM and PM between 2003 and 2007. RESULTS: A total of 803 DM and 500 PM cases were identified between 2003 and 2007. Mean age at diagnosis was 44·0 ± 18·3 years for DM and 49·2 ± 15·9 years for PM. The overall annual incidences of DM and PM were 7·1 (95% CI 6·6-7·6) and 4·4 (95% CI 4·0-4·8) cases per million population. The incidence of both DM and PM increased with age and reached a peak at age 50-59 years. One hundred and eleven (13·8%) patients with DM and 31 (6·2%) patients with PM had cancers. The diagnosis of most cancers was made after the diagnoses of DM (n = 71; 64·0%) and PM (n = 21; 67·7%). Overall, the standardized incidence ratios (SIR) for cancer were 5·36 (4·12-6·87) and 1·80 (1·10-2·79) among patients with DM and PM; however, during the first year, SIRs for cancer were 24·55 (95% CI 18·62-31·79) and 9·17 (95% CI 14·82-15·93) in patients with DM and PM, respectively. The most common types of cancer were nasopharyngeal cancer for men and breast cancer for women. Patients with DM and PM had standardized mortality ratios of 7·68 (6·41-9·01) and 5·29 (4·28-6·48). CONCLUSION: This study reports robust estimates of important aspects of the epidemiology of both DM and PM in Taiwan. This highlights the rarity of these diseases, and their associated cancer risks and increased mortality.

Hyperuricaemia and accelerated reduction in renal function.

OBJECTIVES: Hyperuricaemia has been linked to reduced renal function, and evidence indicates that it may be associated with acceleration of the decline in glomerular filtration rate (GFR) and progression of chronic kidney disease (CKD). METHODS: We analysed a population of subjects who had undergone serum uric acid (SUA) and serum creatinine measurements in a hospital-based cohort. Initial and final serum creatinine measurements were used to calculate the estimated glomerular filtration rate (eGFR) and the annual decline in eGFR. Cox regression was used to investigate the relationship between SUA and CKD progression. RESULTS: A total of 63,785 subjects were enrolled in the study during a 12-year follow-up period. The mean age at the time of initial serum creatinine measurement was 50.0 ± 14.9 years. Hyperuricaemic subjects had a significantly larger annual eGFR decline, both in absolute terms (2.5 ± 9.5 mL/min/1.73 m(2) per year) and as a percentage (2.8 ± 11.6% per year), as compared to the normouricaemia group (1.3 ± 9.6 mL/min/1.73 m(2) per year, 1.1 ± 11.1% per year, p < 0.001). After adjustment for age, sex, status of diabetes mellitus (DM) and hypertension, baseline eGFR, azotaemia, hypercholesterolaemia, and hyperglycaemia, hyperuricaemia was associated with a hazard ratio (HR) of 1.28 [95% confidence interval (CI) 1.23-1.33, p < 0.001] for an accelerated eGFR decline ≥ 3 mL/min/1.73 m(2) per year and an HR of 1.52 (95% CI 1.46-1.59) for CKD progression at the end of follow-up. CONCLUSION: Hyperuricaemia was associated with an accelerated decline in eGFR and higher risk of CKD progression. Therefore, renal function should be monitored closely in patients with hyperuricaemia.

Epidemiology and mortality of systemic sclerosis: a nationwide population study in Taiwan.

OBJECTIVES: There have been few nationwide population studies of systemic sclerosis (SSc). We describe the epidemiological features of SSc in Taiwan. METHODS: The catastrophic illness registry of the Taiwan National Health Insurance Research Dataset (NHIRD) and the National Death Registry of Taiwan were used to calculate estimates of the incidence, prevalence, and mortality of SSc. RESULTS: A total of 1479 persons (325 males, 1154 females) with incident SSc were enrolled in the study. The annual incidence of SSc in Taiwan was found to be 10.9 cases (4.7 males, 17.4 females) per million population. During 2002-2007, the mean prevalence was 56.3 cases per million population. There were 204 deaths (70 males, 134 females) during the study period; 1-, 2-, and 5-year survival rates were 94.9, 92.0, and 83.2%, respectively. SSc patients had a standardized mortality ratio (SMR) of 3.24 [95% confidence interval (CI) 2.82-3.71] for all-cause mortality, as compared with the national population in 2002. There was excess mortality from neoplasms (SMR 1.50, 95% CI 1.03-2.11), cardiovascular diseases (2.23, 1.52-3.16), kidney disease (4.67, 2.66-7.64), gastrointestinal diseases (2.50, 1.27-4.46), and pulmonary diseases (3.20, 1.89-5.09). In addition to male sex and older age, cancer and end-stage renal disease (ESRD) diagnosis were risk factors for death, with hazard ratios (HRs) of 2.71 (95% CI 1.27-5.76) and 2.59 (1.14-5.90), respectively. CONCLUSION: SSc patients had a threefold greater risk of all-cause mortality than the general population of Taiwan. Male sex, older age, diagnosis of cancer, and ESRD were risk factors for death.

Antinuclear antibody status and risk of death in children and adolescents.

OBJECTIVES: The association between the presence of antinuclear antibodies (ANA) and mortality has been rarely reported. The present study explored the value of ANA as a predictor of overall survival in children and adolescents. METHODS: Patients younger than 20 years who underwent ANA testing in Chang Gung Memorial Hospital (CGMH) from 2000 to 2008 were enrolled in this study. Mortality was ascertained by using the National Death Registry of Taiwan. Positive ANA titres were categorized as low (1:40 to 1:80), medium (1:160 to 1:320), and high (≥ 1:640). RESULTS: A total of 13 345 subjects (6579 males, 6766 females) were enrolled during the 9-year study period. The overall prevalence of low, medium, and high ANA titres was 20.8% (n = 2774), 6.0% (n = 804), and 2.5% (n = 338), respectively. During 45,140 person-years of follow-up, 146 deaths were identified and the crude mortality rates were 3.8 and 3.0 per 1000 person-years for subjects with positive and negative ANA test results, respectively (p = 0.130). Compared with ANA-negative subjects, the adjusted hazard ratio (HR) for all-cause mortality among those with a high ANA titre was 5.18 [95% confidence interval (CI) 3.13-8.57]. A low-to-medium ANA titre was not associated with increased mortality. Among the 18 deaths in individuals with a high ANA titre, 14 were due to systemic lupus erythematosus (SLE). In comparison, five out of 34 deaths among those with low-to-medium titres of ANA and none of those with negative ANA were related to SLE. CONCLUSIONS: Children and adolescents with high ANA titres should receive greater attention and monitoring to prevent unfavourable outcomes because they have a higher mortality risk than those with negative ANA results.