Search

: Knowledge of the correspondence between clinical ICD diagnoses and classification criteria fulfilment is crucial to interpret studies identifying cases via ICD codes. We assessed the degree to which patients registered with ICD-10 diagnoses of psoriatic arthritis (PsA) in the Swedish National Patient Register (NPR) fulfil established PsA classification criteria. Four hundred patients with at least one outpatient visit to one of five rheumatology or internal medicine departments (three university/two county departments across Sweden) in 2013–2015, with a main ICD-10 diagnosis of PsA (L40.5, M07.0–M07.3), were randomly selected (80 cases/site). Through a structured medical record review, positive predictive values (PPVs) for fulfilment of the following classification criteria were assessed: CASPAR, Moll and Wright, Vasey and Espinoza, and modified ESSG criteria for PsA. A subset analysis regarding CASPAR fulfilment was also performed among cases with available rheumatoid factor and peripheral X-ray status (central CASPAR items; n = 227). Of the 400 patients with a main ICD-10 diagnosis of PsA, 343 (86%) fulfilled at least one of the four PsA classification criteria. PPVs for the different criteria were: CASPAR 69% (82% in the subset analysis), Moll and Wright 51%, Vasey and Espinoza 76%, and modified ESSG 64%. Overall, only 6.5% of the 400 PsA diagnoses were judged as clearly incorrect by the medical record reviewers. The validity of rheumatologist-made, clinical ICD-10 diagnoses for PsA in the Swedish NPR is good, with PPVs of 69–82% for CASPAR fulfilment and 86% for meeting any established PsA classification criteria. [ABSTRACT FROM AUTHOR]

To assess the validity of venous thromboembolism (VTE) diagnoses registered in the Swedish National Patient Register (NPR) in patients with rheumatoid arthritis (RA). We performed a validation study using manual chart reviews to validate ICD-10 codes for VTE from the NPR. We took a random sample of 269 VTE events registered at hospitals in Region Stockholm from 2009 to 2018 in patients with RA. Medical records for all 269 VTE events were available for review. Overall, the positive predictive value (PPV) for a VTE diagnosis was 95%. For incident VTE events, the PPV was 87% and ranged from 80% to 98% across six more or less restricted alternative definitions of incident VTE event. Out of 235 confirmed incident VTE events, the vast majority were diagnosed independently of the RA disease (three cases occurred as a result of clinical work-up for a presumed RA-related sign or symptom, and in 17 cases did the work-up involve a rheumatologist). This study demonstrates high validity for VTE diagnoses recorded in the NPR for patients with RA, thus confirming that the NPR may be used to identify prevalent VTE as well as incident VTE events in patients with RA. Our results further demonstrate that in patients with RA, diagnoses of VTE are only marginally influenced by work-up related to the rheumatic disease, suggesting a modest impact of surveillance or diagnostic bias. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether low social support or low decision latitude at work correlate with risk of rheumatoid arthritis (RA), and whether and how those factors are associated with known modifiable risk factors for RA. Method: The Swedish population-based EIRA study included, from 1996 to 2015, 3724 incident RA cases and 5935 controls, matched for age, gender, and residential area. Participants filled in detailed questionnaires at diagnosis. Using logistic regression, we investigated whether low social support and low decision latitude at work were associated with RA risk, and whether and how these exposures are associated with known modifiable risk factors for RA. Results: Low decision latitude at work was associated with RA risk in unadjusted analyses [odd ratio (OR) = 1.52, 95% confidence interval (CI) = 1.20–1.94], but this association was weakened after adjustment for known RA risk factors (adjusted OR = 1.24, 95% CI = 0.93–1.63). Low social support was not associated with RA risk (unadjusted OR = 1.05, 95% CI = 0.95–1.15). Cases reporting low decision latitude were more often smokers (OR = 2.05, 95% CI = 1.33–3.16), without university degrees (OR = 8.23, 95% CI = 5.13–13.22), and more often female (OR = 2.52, 95% CI = 1.66–3.81), with a similar pattern among controls. Cases reporting low social support were more often men (OR = 1.60, 95% CI = 1.40–1.83), smokers (OR = 1.46, 95% CI = 1.26–1.70), obese (OR = 1.29, 95% CI = 1.09–1.54), physically inactive (OR = 2.78, 95% CI = 1.98–3.90), and without university degrees (OR = 2.04, 95% CI = 1.77–2.36), with a similar pattern among controls. Conclusion: Low decision latitude coexisted with several known environmental/social risk factors for RA, together defining groups of individuals at increased risk of RA. These risk factors should be viewed in context when testing actions to diminish RA risk in prospective studies. [ABSTRACT FROM AUTHOR]

Objective: To examine lymphoma subtypes, clinical characteristics, and gender differences in patients with primary Sjögren's syndrome (pSS) and lymphoma in a population-based setting.Method: Patients with Sjögren's syndrome and lymphoma diagnoses were identified by linkage of the Swedish Patient Register 1964-2007 with the Cancer Register 1990-2007. Clinical data were collected from medical records and lymphoma tissues were re-examined. The lymphoma subtype distribution was compared with the Swedish Lymphoma Register.Results: We identified 105 pSS patients with lymphoma. Diffuse large B-cell lymphoma (DLBCL) (32%) and marginal zone lymphoma [MZL including mucosa-associated lymphoid tissue (MALT) lymphoma] (31%) were the most common lymphoma subtypes. The proportion of DLBCL was not increased compared to the general population reference (32%, p = 1), in contrast to MZL (general population 5%, p < 0.0001). Compared to DLBCL, MALT lymphoma was diagnosed at a younger age (55 vs 67 years, p = 0.0001), and earlier after patient-reported sicca onset (7 vs 18 years, p = 0.0001) and pSS diagnosis (2 vs 9 years, p = 0.0005). Sixteen of the pSS-lymphoma cases were men (15%), twice the proportion in general pSS populations. Compared to women, men had a shorter median time from pSS diagnosis to lymphoma diagnosis (1 vs 8 years, p = 0.0003) and more often had lymphoma in the salivary glands (56% vs 29%, p = 0.04).Conclusion: DLBCL and MZL are common in pSS patients, but only MZL/MALT lymphoma occurs at an increased relative frequency in pSS compared to the general population. The study supports increased awareness of signs of lymphoma in men in the first years after pSS diagnosis. [ABSTRACT FROM AUTHOR]

Objective: In the 2016 American College of Rheumatology/European League Against Rheumatism classification criteria for primary Sjögren's syndrome (pSS), pre-existing lymphoma is not an exclusion criterion for pSS diagnosis, as in earlier criteria. We aimed to explore whether there are differences between pSS patients with and without pre-existing lymphoma at pSS diagnosis.Method: Patients with ICD-7-10 codes for Sjögren's syndrome (SS) and a diagnosis of malignant lymphoma before or after SS diagnosis were identified by linking the Swedish Patient Register 1964-2007 with the Cancer Register 1990-2007 (n = 224). Clinical data were collected from medical records. Lymphoma diagnoses were evaluated by tissue review. Characteristics of pSS patients with and without pre-existing lymphoma were compared.Results: We identified 107 patients with pSS as the reason for an SS diagnosis code and a verified lymphoma. Of these, 18 (17%) had a pre-existing lymphoma at pSS diagnosis, defined as lymphoma diagnosed before or within 6 months of pSS diagnosis. Male gender (39% vs 10%, p = 0.006), enlarged lymph nodes during the pSS disease (61% vs 27%, p = 0.01), mucosa-associated lymphoid tissue (MALT) lymphoma (50% vs 22%, p = 0.02), and salivary gland lymphoma (61% vs 26%, p = 0.006) were more common in patients with a pre-existing lymphoma at pSS diagnosis. Other pSS characteristics were similar.Conclusion: In a substantial proportion of patients, particularly in men, pSS remains undiagnosed until after lymphoma diagnosis. The study highlights the importance of pSS investigation in patients with lymphoma, especially MALT lymphoma, in the salivary glands. [ABSTRACT FROM AUTHOR]

Objectives: Patients with rheumatoid arthritis (RA) are at increased risk of lymphoma. There is no biomarker to indicate future lymphoma risk in RA and it is not known whether factors associated with an increased risk of RA also confer an increased risk of lymphoma. We investigated whether anti-cyclic citrullinated peptide (CCP) antibodies, other autoantibodies, and smoking, are associated with lymphoma development in RA.Method: From two population-based case-control studies, the Scandinavian Lymphoma Etiology (SCALE) study and the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) I study, we identified lymphoma cases with a validated RA diagnosis (n = 50), to whom we matched study participants with RA but no lymphoma (n = 261), lymphoma but no RA (n = 257), and neither RA nor lymphoma (n = 233). Lymphomas were classified according to the WHO classification. Blood samples were analysed for immunoglobulin G (IgG), IgM, and IgA isotypes and IgG1-4 subclasses of anti-CCP antibodies and for 15 antinuclear antibody (ANA)-associated specific autoantibodies. Relative risks were estimated as crude and adjusted odds ratios (adjOR) with 95% confidence intervals (CIs) using logistic regression.Results: We found no association between anti-CCP IgG ≥ 25 units/mL (adjOR 1.4, 95% CI 0.7-2.7), anti-CCP IgG ≥ 500 units/mL (adjOR 1.4, 95% CI 0.7-3.0), anti-CCP Ig of other isotypes, other autoantibodies (adjOR any vs none 0.6, 95% CI 0.3-1.2), or cigarette smoking (adjOR ever vs never 1.1, 95% CI 0.5-2.2) and lymphoma risk among patients with RA.Conclusion: In this study, neither anti-CCP antibodies (IgG, IgG1-4, IgM, or IgA), nor other common autoantibodies, nor smoking predicted lymphoma risk in RA. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to estimate rates and type of definitive surgical interventions for nephrolithiasis in Swedish patients with ankylosing spondylitis (AS) compared to the general population. Materials and methods. This national prospective cohort study linked data from Swedish population and healthcare registries. Incidence rates and interventions for nephrolithiasis during follow-up in patients with AS were compared to general population comparator (GPC) subjects. Results. In total, 8572 AS patients were followed for 49,959 person-years and 39,639 matched GPCs were followed for 225,221 person-years. Mean age at study entry was 46 years [interquartile range (IQR) 36–56 years] and 65% were male. In AS patients with a diagnosis of nephrolithiasis during the study period, 29% (72/250) underwent similar intervention for nephrolithiasis compared to 24% (114/466) GPCs (p = 0.21). The incidence rate ratio (RR) in overall AS patients was 2.9 [95% confidence interval (CI) 2.1–3.8] during a median follow-up of 6.2 years (IQR 3.2–8.6 years). With prior diagnosis of nephrolithiasis, the RR for AS patients compared to GPCs was 3.7 (95% CI 1.8–7.7); without prior nephrolithiasis the RR was 2.1 (95% CI 1.5–3.0). Increasing age [odds ratio (OR) 1.02, 95% CI 1.01–1.03], prior nephrolithiasis diagnosis (OR 3.3, 95% CI 1.97–5.62) and atherosclerotic cardiac disease (OR 2.0, 95% CI 1.03–3.91) were identified as predictors of intervention for nephrolithiasis. Conclusions. Patients with AS have an almost three-fold increased risk of surgical intervention for kidney stones, with similar management, compared to the general population. [ABSTRACT FROM AUTHOR]

Objectives: Evidence regarding the efficacy and effectiveness of certolizumab pegol (CZP) in rheumatoid arthritis (RA) patients who have failed to respond to treatment with a tumour necrosis factor inhibitor (TNFi) is limited. The aim of this study was to describe the effectiveness and survival-on-drug of CZP in a real-life setting, both in TNFi-naïve patients and in patients who had previously failed TNFis, and in relation to disease activity at baseline.Method: The national Swedish Rheumatology Quality Register (SRQ) was used to identify patients with RA starting treatment with CZP between 2009 and 2013. The effectiveness of treatment was assessed using the 28-joint Disease Activity Score (DAS28), the Health Assessment Questionnaire (HAQ), measures of remission, the European League Against Rheumatism (EULAR) response during 0-6 months from start of treatment, and survival-on-drug during the first 30 months.Results: A total of 945 RA patients started treatment with CZP. Of these, 540 (57.1%) received CZP as the first biological treatment, 215 (23%) had failed one previous TNFi, and 190 (20%) had failed at least two TNFis. Overall, 71% achieved at least a EULAR moderate response and 38% had a EULAR good response at 6 months from baseline. TNFi-naïve patients achieved significantly better results and had better survival-on-drug compared to patients who had failed previous TNFis. Around 20% of patients who had not responded to two or more prior TNFis achieved EULAR good response to therapy and a similar percentage achieved remission. Patients who had high baseline disease activity had a higher risk of discontinuing treatment compared to those without high disease activity.Conclusions: In this real-life RA cohort, CZP was associated with significant clinical improvement. The effectiveness and survival-on-drug vary markedly depending on the line of treatment. [ABSTRACT FROM AUTHOR]

Objectives: Epidemiological studies of spondyloarthritis (SpA), using ICD codes from the Swedish National Patient Register (NPR), offer unique possibilities but hinge upon an understanding of the validity of the codes. The aim of this study was to validate the ICD codes for ankylosing spondylitis (AS) and undifferentiated SpA (uSpA) in the NPR against the established classification criteria [modified New York (mNY), Assessment of SpondyloArthritis international Society (ASAS), Amor, and European Spondyloarthropathy Study Group (ESSG) criteria].Method: All patients with an ICD-8/9/10 code of AS or uSpA in the NPR 1966-2009 at a visit to a specialist in rheumatology or internal medicine or corresponding hospitalization, alive and living in Sweden 2009, were identified (n=20,089). Following a structured procedure to achieve geographical representativeness, 500 random patients with a diagnosis of AS or uSpA in 2007-2009 were selected. Based on a structured review of clinical records, positive predictive values (PPVs) for fulfilling the criteria sets were calculated.Results: For those having received an ICD code for AS, the PPVs for fulfilling the mNY criteria or any set of SpA criteria were 70% and 89%, respectively. For those with an uSpA diagnosis (and never an AS diagnosis), the corresponding PPVs were 20% and 79%. The subset with both AS and uSpA diagnoses (overlap=12%) were as likely to fulfil the mNY criteria as the group that had been coded as AS only.Conclusions: The diagnosis codes for AS or uSpA had high PPVs, suggesting that our case identification in the Swedish NPR can be used for nationwide, population-based, epidemiological studies of these diseases. [ABSTRACT FROM AUTHOR]

Objectives: To assess the coverage of the Swedish Biologics Register (Anti-Rheumatic Therapy in Sweden, ARTIS) across indications, and the accuracy of the registered information on treatment with biologics. Method: Through cross-reference of ARTIS to almost complete national health registers on prescriptions (adalimumab and etanercept), outpatient visits, and death/residency during 2008–2010, we assessed: the treatment coverage of ARTIS for each treatment indication, the validity of the registered start and stop dates, ARTIS treatments with no corresponding drug dispensations, and the accuracy of the registered information on concomitant anti-rheumatic therapies. Results: According to the national health registers, 3945 individuals with a spondyloarthropathy (SpA) and 8032 patients with rheumatoid arthritis (RA) had filled at least one adalimumab or etanercept prescription during the study period. Of these, 86% of those with SpAs and 95% of patients with RA were also found in ARTIS with the corresponding treatment. Tumour necrosis factor (TNF) inhibitor prescriptions had been filled by 95% of patients between the ARTIS start and stop dates (allowing a 90-day window). More than 60 days before and more than 60 days after the registered start date in ARTIS, 5% and 4% respectively of patients had filled their first TNF inhibitor prescription. More than 90 days after the registered stop date in ARTIS, 8% of patients had filled one or more TNF inhibitor prescriptions. Conclusions: We observed a high coverage and accuracy of ARTIS data on biologics exposure, for both SpAs and RA. The combination of data from clinical registers such as ARTIS with data from national health registers offers a high quality measurement of actual treatment. [ABSTRACT FROM AUTHOR]

Objective: To measure small-area variations in sales per capita of tumour necrosis factor (TNF) inhibitors. Methods: For 2000-2009, sales data on etanercept, infliximab, and adalimumab were retrieved from the Swedish National Corporation of Pharmacies, which keeps data on drugs dispensed in ambulatory care and hospitals. As points of reference, data were retrieved on all drugs, non-biologic treatments for chronic inflammatory disorders (sulfasalazine, methotrexate, azathioprine), and for a biologic used in a different therapeutic area (trastuzumab). As a corollary measure to sales per capita, penetration of biologics in the rheumatoid arthritis (RA) population was calculated using nationwide registers. Small areas were defined as the 21 counties of Sweden. Results: From 2000 to 2009, annual TNF inhibitor sales increased 9-fold from 195 to 1779 million SEK (0.7-5.0% of total drug expenditure). The county variation in sales per capita, initially 6.2-fold (coefficient of variation 42%), decreased to 2.3-fold in 2009 (24%). During the same period, total drug expenditure per capita remained at a 1.2-fold county variation (4-6%). Sales per capita variations of non-biologic treatments against chronic inflammatory diseases ranged from 1.5 to 1.8 (12-16%). For trastuzumab, a 3.2-fold variation (30%) was observed in 2009. At the patient level, there was a 2-fold county variation (from 10% to 21%) in biologic penetration in RA. County-specific sales per capita were associated with mean RA duration (r = −0.52, p = 0.015) and C-reactive protein at treatment initiation (r = −0.49, p = 0.025), while pain was borderline significant (r = −0.43, p = 0.055). Conclusions: Despite universal access to treatment, substantial but decreasing small-area variations were observed. Although geographic variations are anticipated initially, their persistence calls for investigation of patient equity and treatment appropriateness as counties seem to have different initiation thresholds. [ABSTRACT FROM AUTHOR]