Ann Rheum Dis 2017;76: doi: /annrheumdis Lin, Wan-Ting 2018/05/161

Transcription

1 Ann Rheum Dis 2017;76: doi: /annrheumdis Lin, Wan-Ting 2018/05/161

2 Introduction We and others have previously demonstrated an increased risk of acute coronary syndrome (ACS) in patients with RA compared with the general population, already within a few years of the RA diagnosis. the mechanisms behind this risk increase are not completely elucidated Few studies have, however, addressed the risk of ACS in RA over calendar time periods and disease duration with focus on patients diagnosed with RA during the most recent decade. 2

3 Aim The aim of this study was therefore to investigate whether improved management in terms of treatment options, treatment algorithms and cardiovascular vigilance in new-onset RA collectively have led to a reduction in the excess risk of ACS. 3

4 Design and setting Design We performed a nationwide population-based cohort study of patients with newly diagnosed with matched general population comparator subjects, based on prospectively recorded register data. Setting The publicly funded Swedish healthcare system enables access to all healthcare services, including specialized care for chronic diseases such as RA, for all residents. All residents are assigned a unique personal identity number that can be used for linkage of different data resources, including several national health registers of high quality. 4

5 The new-onset RA cohort Swedish Rheumatology Quality (SRQ) Register initiated in 1995 and includes individuals aged 16 years or older fulfilling the 1987 American College of Rheumatology criteria for RA The current coverage (on a national basis) is estimated to above 80% of all new-onset RA. age, sex, rheumatoid factor (RF) status, date of first symptom of RA, date of inclusion into the register, the personal identification number and drug treatment and disease activity We identified all individuals diagnosed with RA between 1 January 1997 and 31 December 2014 who were included in the register within 12 months of first symptoms of RA (n=16 214). less than 0.8% of all new-onset RA in SRQ represents prevalent RA misclassified as new-onset the date of inclusion into the register (typically the date of RA diagnosis) was used as index date. 5

6 General population comparators cohort For each unique patient with RA, we randomly selected up to five individuals from the Swedish Population Register (which includes all Swedish residents), matched on sex, year of birth and residential area (n=72 939). Each subject was assigned the same index date as the corresponding patient with RA. 6

7 Data sources The National Patient Register contains information on inpatient care since 1964, with nationwide full coverage since 1987 date of admission, date of discharge and the discharge diagnosis (primary and secondary diagnoses) as set by the discharging physician and classified according to the calendar year-specific version of the International Classification of Diseases (ICD, since 1997: ICD-10) The Population Register includes information on deaths, emigration and immigration for the entire Swedish population The Cause of Death register cause of death coded according to ICD The Integrated Database for Labor and Education educational level 7

8 Follow-up and occurrence of ACS ACS was defined as hospitalization listing a primary ICD-10 diagnosis of I21 (acute myocardial infarction) or I20.0 (unstable angina pectoris), or an acute myocardial infarction listed as the underlying cause of death. all individuals with a diagnosis of ACS prior to the start of follow-up were excluded The RA cohort and the comparison cohort were followed from the index date until the first ACS, death, emigration or 31 December 2014, whichever came first. 8

9 Statistical analysis Incidence rate overall and in subgroups based on sex, age and calendar year of diagnosis The excess incidence of ACS was defined as the difference between the incidence in the RA cohort and the corresponding incidence in the general population cohort. Hazard ratio using Cox regression models adjusted for residential area, sex, year of diagnosis, age at diagnosis and educational level. Analyses were stratified by RF status, sex, age at index date, calendar period of index date, time since start of follow-up and DAS28 ( 3.2 and >3.2) at RA diagnosis. 9

10 Results Means: 57 10

11 Results 11

12 Results (median/iqr follow-up=5.7/7.1 years) (median/iqr follow-up=5.7/7.3 years) 增加 40% 風險 1685(10.7%) of patient of RA and 7336(10.4%) of general population subject died. 12

13 Results 13

14 Results 14

15 Discussion Because the decline in incidence was equally pronounced in the RA cohort as in the general population, there was no evidence of any decline in the excess risk for patients diagnosed with RA in more recent years. Published studies evaluating time trends in CVD incidence in RA cohorts comprising patients with disease debut after 2000 are scarce. Our observation of a rapid increase in the risk of ACS after RA diagnosis is in line with our previous results from this cohort and the results from other studies. 15

16 Study strength The main strength of this study is the large, nationwide, population-based RA inception cohort, with the possibility to add prospectively collected and linked data on comorbidity and covariates from mandatory public registers. Also, the Swedish RA treatment guidelines are in good agreement with most other RA guidelines, at least in the western world. Therefore we believe that our results may also be applicable to other settings other than Sweden. 16

17 Study limitation Although this is a large cohort, the numbers of events in some strata were low. We did not have data on traditional risk factors for patients or referents The frequencies of unidentified but true ACS (eg, silent myocardial infarction) in the RA and comparator cohorts are unknown, but based on previous studies unlikely to be higher among the general population comparator subjects. 17