P. Drivelegka

Incidence of and risk factors for nephrolithiasis in patients with gout and the general population, a cohort study

BackgroundNephrolithiasis (NL) is known to be associated with gout, although there are few comparative studies on risk and risk factors for NL in gout compared to population cohorts. In this cohort study we investigated: (1) overall incidence of NL in gout (cases) and general population controls; (2) risk and risk factors (common comorbidities and medications) for first-time NL in cases and controls separately.MethodsCases (n = 29,968) and age-matched and sex-matched controls (n = 138,678) were identified from the regional healthcare database in western Sweden (VEGA). The analyzed risk factors (comorbidities and current medication use) for first-time NL, and socioeconomic factors were retrieved from VEGA and other national Swedish registers. For cases, follow up began on 1 January 2006 or on the first diagnosis of gout if this occurred later, and for controls on their index patient’s first diagnosis of gout. Follow up ended on death, emigration or 31 December 2012. Incidence rates (IR) per 1000 person-years and hazard ratios (HR) were calculated. The incidence calculations were performed for cases (regardless of prior NL) and their controls. HRs with first occurrence of NL as outcome were calculated only in those without previous NL.ResultsIn cases there were 678 NL events (IR: 6.16 events per 1000 person-years (95% CI: 5.70–6.64) and in controls 2125 NL events (IR 3.85 events per 1000 person-years (95% CI: 3.69–4.02), resulting in an age-sex-adjusted incidence rate ratio of 1.60 (95% CI:1.47–1.74).Point estimates for predictive factors were similar in cases and controls, except for a significant interaction for losartan which increased the risk of NL only in controls (HR = 1.49 (95% CI: 1.03–2.14). Loop diuretics significantly decreased the risk of NL by 30–34% in both cases and controls. Further significant predictors of NL in gout cases were male sex, diabetes and obesity and in controls male sex and kidney disease.ConclusionsThe risk (age and sex adjusted) of NL was increased by 60% in cases compared to controls. None of the commonly used medications increased the risk of NL in gout patients.

Work disability in gout: a population-based case–control study

Objectives To examine the extent and cost of work disability among patients with gout compared with matched population controls and to analyse predictors of work disability. Methods A regional cohort study using data from Swedish national and regional registries from January 2000 through December 2012, including 4571 patients with gout of working age, with a first recorded diagnosis of gout in the years 2003–2009 and 22 482 population controls, matched by age, sex and place of residence. Differences in baseline characteristics (educational level, income, previous employment and comorbidities) and the number of work-loss days (absenteeism) due to sick leave and disability pension for 3 years after identification were calculated. Predictors for new-onset work absenteeism (>90 days/year) in a subset were determined by conditional logistic regression. Results Patients with gout (median age 53 years) had significantly more comorbidities, lower income and lower level of education than matched controls. The average work absentee rate during the 3-year follow-up period was higher among patients with gout than controls, 22% and 14%, respectively (P<0.0001). New-onset absenteeism was in multivariate analyses significantly predicted by gout (OR 1.47; 95% CI 1.23 to 1.75). Other variables independently related to new-onset absenteeism were education ≤12 years, previous unemployment and history of sick leave, in addition to several comorbidities (renal disease, cardiovascular disease, alcohol abuse and obesity). Conclusions Gout is associated with substantially higher work absenteeism and costs for society due to productivity loss, after adjusting for associated comorbidities and socioeconomic differences. Whether more intensive treatment of gout is cost-effective needs to be addressed in future studies.

OP0262 Trends and costs for gout hospitalization in sweden

Background Gout is the most common arthritic disease in the world with increasing incidence and prevalence. There are differences in gout prevalence and course of disease due to cultural, ethnical and genetic factors stressing the need for data from different parts of the world. An increase in hospitalization for gout has been shown for the last two decades in North America. Objectives We evaluated the trend for hospitalization of gout in western Sweden 2000 – 2012 and the health care costs for this 2009 – 2012. Methods Hospitalization trends for gout were studied using data from the health care consumption register in the Western Swedish Health Care Region (WSHCR) from 2000–01–01 through 2012–12–31. This area is considered to be representative for the country as a whole. Patients aged 18 years and older who were hospitalized during the study period with a principal ICD-10 diagnosis of gout (M10) at discharge were included. We calculated annual population rates for hospitalization for gout. Inflation-adjusted health care costs for the gout hospitalizations were calculated using the Cost-Per-Patient register (CPP). Dispensation of urate lowering therapy (ULT), allopurinol (M04AA01) and probenecid (M04AB01), within 6 months prior to hospitalization was identified using The Swedish Prescribed Drug Register. Results There were 1873 hospitalizations for gout (mean age 75.0–77.6 years, 61–74% men) between 2000 and 2012. Demographic characteristics were similar over the study period. From 2000 to 2012, the annual hospitalization rate for gout increased from 12.2 to 16.7 per 100 000 adults (p=0.0038). The increase was most pronounced in males aged 65 and above and over the last three years of the study. From 2009 to 2012 the inflation-adjusted health care costs for gout hospitalizations increased from 5.21 to 8.15 105 USD. The duration of hospitalizations also increased from 3 to 5 days median 2000 and 2012 respectively (p=0.021). Only a minority of patients, 19 to 27%, received ULT the 6 months preceding their hospitalization, without any obvious secular trend.Table 1 2000 2002 2004 2006 2008 2009 2010 2011 2012 Discharges, no 142 112 108 133 140 144 187 180 213 Incidence per 100 000 adults 12.2 9.5 9. 1 11.0 11.3 11.5 14.9 14.2 16.7 Men, incidence per 100 000 adults 16.1 12.3 12.9 14.4 15.7 16.0 22.0 21.1 24.3 Women, incidence per 100 000 adults 8.4 6.8 5.3 7.7 7.0 7.1 7.9 7.3 9.1 Duration, days, median (range) 3 (1–71) 3 (1–44) 5 (1–75) 5 (1–65) 5 (1–40) 5 (1–39) 5 (1–34) 5 (1–52) 5 (1–41) Age, years, mean, SD 76.2 (12.1) 74.3 (14.9) 76.3 (11.7) 77.2 (10.2) 77.4 (11.4) 76.7 (11.6) 77.6 (12.7) 75.6 (14.1) 75.0 (13.8)  18–44 3 6 1 0 5 4 8 8 4  45–64 23 16 17 19 12 11 19 28 41  65–84 83 63 67 80 85 89 100 92 108  ≥85 33 27 23 34 38 40 60 52 60 ULT, (%), 6 months before hospitalization 28 (21) 38 (27) 27 (19) 38 (20) 47 (26) 45 (21) Total cost*, 105 USD 5.21 6.8 6.6 8.15 Conclusions Incidence of hospitalization for primary gout is increasing substantially in Sweden over the last decade and this is reflected in the health care costs. The main part of this increase consists of males aged 65 and above. Only a fourth of the patients were on ULT preceding the hospitalization. These findings are further emphasized by the fact that the total amount of days for somatic inpatient care in WSHCR decreased by 9% from 2002 (1 267 900 days, mean duration 5,7 days) to 2012 (1 151 630 days, mean duration 4,9 days). The findings in this study reflects increasing incidence of the gout disease and an ageing population but also a considerable lack of treatment. Disclosure of Interest None declared

AB0831 Low Education Level as A Predictor of Gout in Western Sweden: Table 1.

Background Gout was previously regarded a disease of the affluent. Knowledge about the association between gout and socioeconomic status in modern times is limited. Objectives To investigate the association between gout and socioeconomic factors in a population based register study in a large region in Sweden. Methods All patients receiving ≥2 diagnoses of gout on at least two separate occasions in primary or secondary care or 1 diagnosis by a specialist in Rheumatology in Västra Götaland in the years 2007–2012 were identified by ICD10 codes in a regional database of health-care utilization. 3189 such patients were identified. The date of the first diagnosis was defined as the index date. A previous validation study of cases identified in this manner confirmed that this case definition is highly consistent with a diagnosis of gout as defined by established criteria (PPV >80%)(1). For each case, up to 5 controls matched for age, gender and place of residence at the time of the first gout diagnosis were chosen by the Statistics Sweden agency (SCB) (N=14946). Common comorbidities known to be associated with gout (ischemic heart disease, heart failure, atrial fibrillation, hypertension, hyperlipidemia, diabetes and renal failure) prior to the index date were retrieved from the regional database of health-care utilization based on ICD10-codes. Data on education level and income at the index year was collected from the Longitudinal Integration Database for health Insurance and Labor market studies (LISA). The database holds annual registers since 1990 on all individuals above 16 years of age registered in Sweden. Results Data on education level and income was analyzed for cases and controls belonging to the working-age population as defined in Sweden (aged 15–74 years). Shorter education, <12 years, was significantly more common among cases. Yearly income was lower among cases irrespective of educational length (Table 1). Cases had significantly more pre-index comorbidities compared to the controls. In a subgroup analysis of 1084 cases and 6117 controls of working age without any cardiovascular- or renal comorbidity, educational level and income was still significantly lower among cases (data not shown).Table 1. Education and income for individuals aged 15–74 years Educational length in years Mean yearly income in EUR Cases, N (%) Controls, N (%) p-value Cases Controls p-value ≥12 406 (20) 2730 (28) <0.001 22830 26230 0.037 <12 1598 (79) 6961 (71) 11850 12930 0.021 *1% of cases and controls had missing info on educational length. Conclusions Low education level and income are predictors for gout in the working age population. The effects of education do not seem to be largely/only mediated via cardiovascular- or renal comorbidity, supporting that other factors possibly related to lifestyle or occupational exposures are of importance for gout development. References Dehlin M, Stasinopoulou K, Jacobsson L. Validity of gout diagnosis in Swedish primary and secondary care – a validation study. BMC Musculoskelet Disord. 2015;16:149. Disclosure of Interest None declared

THU0522 Increasing Incidence of Gout in Western Sweden – A Register Study

Background Gout is the most common inflammatory arthritic disease worldwide. The prevalence varies due to cultural, ethnical and genetic differences in populations, which emphasizes the need for national/regional data on occurrence. While there are several studies on the prevalence of gout only few have addressed the incidence of gout and there are no contemporary studies in Sweden and the neighbouring Nordic countries. Objectives In the present study we measured the incidence of gout in 2012 and its trends from 2004 to 2012 in the Western Swedish Health Care Region (WSHCR) in Sweden. Methods We identified all incident cases of gout from 2004 through 2012 through VEGA, a diagnosis register covering all visits to physicians in primary and secondary care and hospitalizations in WSHCR. WSHCR has 1 600 000 inhabitants, roughly 20% of the population of Sweden, and is representative for the country as a whole with regard to demographics and health status. For the analyses of incidence trends an incident case of gout was defined as having a visit with a first ICD-10 diagnosis of gout (M10, M14) not preceded by a diagnosis of gout for the three calendar years before. Cumulative incidence per year was calculated using the number of incident gout cases aged 20 and above by calendar year (from 2004 to 2012) as the numerator and the total person-years aged 20 and above of WSHCR by the end of each year as the denominator. We calculated standardized estimates (direct method) using the whole Swedish population aged ≥20 years in 2012 as standard population Calculation of incidence trend was performed using logistic regression. Incidence in 2012 was based on cases with their first diagnosis of gout 2012 without any such diagnosis during the12 preceding years (2000–2011). All cases were linked to Statistics Sweden (for death and possible emigration before Dec 2012). Results The incidence of gout increased steadily and significantly (p for trend <0.001) from 2004 to 2012 with a 50% increase in the total population. The male to female ratio of gout incidence was consistently two to three fold from 2004 to 2012 (Fig. 1). The incidence of gout in Sweden 2012 was 190 cases per 100 000 person-years. Conclusions Gout is an increasing health care problem all over the world and also in western Sweden where the incidence of gout increased significantly over the last decade being approximately three times higher than that for rheumatoid arthritis. This increase might reflect changes in the disease panoramic and cultural changes. Disclosure of Interest None declared

THU0521 Prevalence of Gout and ULT Treatment in Western Sweden – A Register Study

Background Gout is the most common inflammatory arthritic disease worldwide. The prevalence varies due to cultural, ethnical and genetic differences in populations, which emphasizes the need for national/regional data on occurrence. There are major insights in the pathogenesis and effective treatments have been available for decades. Despite this several earlier reports state sub-optimal treatment with urate lowering therapy (ULT) of this common and severe disease. Contemporary data on whether this has improved recently are overall few and completely lacking from the Nordic countries. Objectives In the present study we measured the prevalence of gout in western Sweden and the proportion thereof treated with ULT. Methods We identified all individuals with one or more ICD-10 diagnosis of gout (M10, M14) in the Western Swedish Health Care Region (WSHCR), Sweden, 2002-01-01 to 2012-12-31 through VEGA, a diagnosis register entailing all visits to physicians in primary and secondary care and hospitalizations in the region with diagnosis according to the Swedish version of ICD-10. WSHCR has 1 600 000 inhabitants, roughly 20% of the population of Sweden and is representative for the country as a whole with regard to demographics and health status. All cases were linked to Statistics Sweden (for death and possible emigration before Dec 2012) and the National Drug Prescription Register (for dispensation of ULT prescriptions during 2012). The point prevalence of gout Dec 2012 was calculated using the number of people aged 20 and above fulfilling our case definitions for gout who were alive and living in WSHCR 2012-12-31 as the numerator and the total population aged 20 and above of WSHCR by 2012–12–31 as the denominator. Dispensation of ULT prescriptions during 2012 were identified for allopurinol, febuxostat and probenecid. The presence of ≥1 dispensation was regarded as ULT treatment in 2012. Results The prevalence of gout in the Swedish population aged 20 years and above was 1,7% overall and increased with age and male sex (Fig 1), and was more than 3% in males above 50 years of age. Only 43% of the patients received treatment with ULT in 2012, almost exclusively allopurinol (99%). Of these 43%, the majority (59%) received a dose of only 100 mg allopurinol daily. Conclusions Gout is the most common inflammatory arthritic disease in Sweden with an overall prevalence of 1.7%. Treatment with ULT is still in 2012 insufficient with low a low proportion being treated and those treated receiving low doses. Disclosure of Interest None declared