Tattoos as a risk factor for malignant lymphoma: a population-based case-control study.

Background: The popularity of tattoos has increased dramatically over the last few decades. Tattoo ink often contains carcinogenic chemicals, e.g., primary aromatic amines, polycyclic aromatic hydrocarbons, and metals. The tattooing process invokes an immunologic response that causes translocation of tattoo ink from the injection site. Deposition of tattoo pigment in lymph nodes has been confirmed but the long-term health effects remain unexplored. We used Swedish National Authority Registers with full population coverage to investigate the association between tattoo exposure and overall malignant lymphoma as well as lymphoma subtypes. Methods: We performed a case-control study where we identified all incident cases of malignant lymphoma diagnosed between 2007 and 2017 in individuals aged 20-60 years in the Swedish National Cancer Register. Three random age- and sex-matched controls per case were sampled from the Total Population Register using incidence density sampling. We assessed exposure through a questionnaire in 2021, and data on potential confounders were retrieved from registers. We used multivariable logistic regression to estimate the incidence rate ratio (IRR) of malignant lymphoma in tattooed individuals. Findings: The study population consisted of 11,905 individuals, and the response rate was 54% among cases (n = 1398) and 47% among controls (n = 4193). The tattoo prevalence was 21% among cases and 18% among controls. Tattooed individuals had a higher adjusted risk of overall lymphoma (IRR = 1.21; 95% CI 0.99-1.48). The risk of lymphoma was highest in individuals with less than two years between their first tattoo and the index year (IRR = 1.81; 95% CI 1.03-3.20). The risk decreased with intermediate exposure duration (three to ten years) but increased again in individuals who received their first tattoo ≥11 years before the index year (IRR = 1.19; 95% CI 0.94-1.50). We found no evidence of increasing risk with a larger area of total tattooed body surface. The risk associated with tattoo exposure seemed to be highest for diffuse large B-cell lymphoma (IRR 1.30; 95% CI 0.99-1.71) and follicular lymphoma (IRR 1.29; 95% CI 0.92-1.82). Interpretation: Our findings suggested that tattoo exposure was associated with an increased risk of malignant lymphoma. More epidemiologic research is urgently needed to establish causality. Funding: The Swedish Research Council for Health, Working Life and Welfare.

Negative Prognostic Impact of Tumor Deposits in Rectal Cancer: A National Study Cohort.

OBJECTIVE: To investigate whether tumor deposits (TDs) in rectal cancer are associated with increased recurrence risk and decreased survival. BACKGROUND: Tumor deposits (TDs) are considered a risk factor for recurrence after colon cancer resection, and the presence of TDs prompts adjuvant chemotherapy. The prognostic relevance of TDs in rectal cancer requires further exploration. METHODS: All patients treated with abdominal resection surgery for rectal cancer in Sweden between 2011 and 2014 were eligible for inclusion in this retrospective cohort study based on prospectively collected data from the Swedish Colorectal Cancer Registry. The primary endpoint was local recurrence or distant metastasis. Secondary outcomes were overall and relative survival. RESULTS: Five thousand four hundred fifty-five patients were identified of which 3769 patients were analyzed after exclusion. TDs were found in 404 (10.7%) patients, including 140 (3.7%) patients with N1c-status. In TD-positive patients, local recurrence and distant metastasis rates at 5 years were 6.3% [95% CI 3.8-8.8%] and 38.9% [95% CI, 33.6-43.5%] compared with 2.7% [95% CI, 2.1-3.3%] and 14.3% [95% CI, 13.1-15.5%] in TD-negative patients. In multivariable regression analysis, the risk of local recurrence and distant metastasis were increased; HR 1.86 [95% CI, 1.09-3.19; P =0.024] and 1.87 [95% CI, 1.52-2.31; P =<0.001], respectively. Overall survival at 5 years was 68.8% [95% CI, 64.4-73.4%] in TD-positive patients and 80.7% [95% CI, 79.4-82.1%] in TD-negative patients. pN1c-patients had similar outcomes regarding local recurrence, distant metastasis, and survival as pN1a-b stage patients. TD-positive pN1a-b patients had significantly worse outcomes whereas TDs did not affect outcomes in pN2a-b patients. CONCLUSION: This study suggests that TDs have a negative impact on the prognosis in rectal cancer. Thus, efforts should be made to diagnose TD-positive rectal cancer patients preoperatively.

Diagnostic codes of cancer in Skåne healthcare register: a validation study using individual-level data in southern Sweden.

BACKGROUND: The Swedish healthcare is decentralised to 21 regions. Detailed information on all delivered care in the southernmost region, Skåne, is prospectively collected in the Skåne Healthcare Register (SHR). The data is updated daily and hence a good source for epidemiological studies. However, the diagnostic codes used to identify cancer patients in SHR have not yet been validated. METHODS: We conducted a validation study including 1,473,204 residents in Skåne region during 2005-2014, with at least one physical consultation in SHR. Newly diagnosed cancer from the Swedish Cancer Register was considered the 'gold standard' reference. We estimated the positive predictive value (PPV), sensitivity, and area under the curve (AUC) of a cancer diagnosis based on SHR by level of consultation, for any cancer, and for different cancer types. RESULTS: There were 61,693 cancers from the Swedish Cancer Register, and 87,650 cancers from SHR. The PPV of SHR-based diagnosis of any cancer was 63.76% (95% confidence interval (CI): 63.44-64.08%) with a sensitivity of 90.58% (95% CI: 90.35-90.81%). The AUC was 0.94, for any cancer. The measures of PPV, sensitivity and AUC varied across levels of care and were higher in specialized care than in primary care. The highest PPV was observed for specialist inpatient care in SHR (89.17, 95% CI 88.89-89.45%) whereas the highest sensitivity was observed for specialized outpatient care in SHR (86.39, 95%CI 86.12-86.66%). Robust validity was noted among most cancers, except for cancers of soft tissues, central nervous system and eye, and endocrine glands. CONCLUSIONS: Our study supports that SHR is a valid and robust healthcare register for cancer diagnosis, with varying validities across levels of care and cancer types. This makes SHR a useful data source for cancer epidemiological studies, especially because the data covers the entire cancer care pathways without time lags for further linkage.

Psychiatric Disorders and Cardiovascular Diseases During the Diagnostic Workup of Suspected Prostate Cancer.

Background: It is unknown whether the rate of psychiatric disorders and cardiovascular disease increases during the diagnostic workup of suspected prostate cancer. Methods: We designed a population-based cohort study including 579 992 men living during 2005-2014 in Skåne, Sweden, according to the Swedish Total Population Register and the Skåne Healthcare Register (SHR). We used the Swedish Cancer Register and the SHR to identify all men with a new diagnosis of prostate cancer (N = 10 996), and all men underwent a prostate biopsy without receiving a cancer diagnosis (biopsy group, N = 20 482) as exposed to a diagnostic workup. Using Poisson regression, we compared the rates of psychiatric disorders and cardiovascular disease during the period before diagnosis or biopsy of exposed men with the corresponding rates of unexposed men. Results: We found an increased rate of psychiatric disorders during the period before diagnosis or biopsy among men with prostate cancer (incidence rate ratio [IRR] = 1.87, 95% confidence interval [CI] = 1.67 to 2.10) and men in the biopsy group (IRR = 2.22, 95% CI = 2.08 to 2.37). The rate of cardiovascular disease increased during the period before diagnosis or biopsy among men with prostate cancer (IRR = 2.22, 95% CI = 2.12 to 2.32) and men in the biopsy group (IRR = 2.56, 95% CI = 2.49 to 2.63). Greater rate increases were noted for a diagnostic workup due to symptoms than due to other reasons. Conclusions: There was an increased risk of psychiatric disorders and cardiovascular disease during the diagnostic workup of suspected prostate cancer regardless of the final cancer diagnosis.

Disease duration, age at diagnosis and organ damage are important factors for cardiovascular disease in SLE.

OBJECTIVE: To report the incidence rate ratios (IRR) of acute myocardial infarctions (AMI) and cerebrovascular events (CVE) in incident SLE cases from a defined population. To study the risk factors for cardiovascular events in all patients with SLE at our unit. METHODS: Patients with SLE diagnosed from 1981 to 2006 were followed through to 2016. IRRs of AMI and CVE were calculated. The AMI and CVE incidence patterns for patients with SLE were studied in relation to hypertension, smoking, renal dysfunction, anticardiolipin (aCL) antibodies at diagnosis, disease duration and organ damage before an event. RESULTS: 262 patients with SLE were included in the study; of these 175 were from the defined population. Overall, 37 AMI and 44 CVE were recorded. An increased IRR of 3 for AMI was found (p<0.001). Smoking, hypertension and reduced renal function were risk factors for AMI. An increased IRR of 3.3 for ischaemic CVE was found for women (p<0.001). Hypertension and aCL were risk factors for CVE. Organ damage before events was increased. CONCLUSIONS: Cardiovascular events are increased in SLE and are associated with hypertension, smoking and increased damage rate.

Cardiovascular Diseases And Psychiatric Disorders During The Diagnostic Workup Of Suspected Hematological Malignancy.

BACKGROUND: Little attention has been given to the risk of cardiovascular and psychiatric comorbidities during the clinical evaluation of a suspected hematological malignancy. METHODS: Based on Skåne Healthcare Register, we performed a population-based cohort study of 1,527,449 individuals residing during 2005-2014 in Skåne, Sweden. We calculated the incidence rate ratios (IRRs) of cardiovascular diseases or psychiatric disorders during the diagnostic workup of 5495 patients with hematological malignancy and 18,906 individuals that underwent a bone marrow aspiration or biopsy or lymph node biopsy without receiving a diagnosis of any malignancy ("biopsied individuals"), compared to individuals without such experience (i.e., reference). RESULTS: There was a higher rate of cardiovascular diseases during the diagnostic workup of patients with hematological malignancy (overall IRR, 3.3; 95% CI, 2.9 to 3.8; greatest IRR for embolism and thrombosis, 8.1; 95% CI, 5.2 to 12.8) and biopsied individuals (overall IRR, 4.9; 95% CI, 4.6 to 5.3; greatest IRR for stroke, 37.5; 95% CI, 34.1 to 41.2), compared to reference. Similarly, there was a higher rate of psychiatric disorders during the diagnostic workup of patients with hematological malignancy (IRR, 2.1; 95% CI, 1.5 to 2.8) and biopsied individuals (IRR, 3.1; 95% CI, 2.9 to 3.4). The rate increases were greater around the time of diagnosis or biopsy, compared to thereafter, for both outcomes. CONCLUSION: There were higher rates of cardiovascular diseases and psychiatric disorders during the diagnostic workup of a suspected hematological malignancy, regardless of the final diagnosis.

Psychiatric disorders and cardiovascular diseases during the diagnostic workup of potential breast cancer: a population-based cohort study in Skåne, Sweden.

BACKGROUND: An increasing number of women are evaluated for potential breast cancer and may experience mental distress during evaluation. We aim to assess the risks of psychiatric disorders and cardiovascular diseases during the diagnostic workup of potential breast cancer. METHODS: All women with a new diagnosis of unspecified lump in breast (N = 15,714), benign tumor or breast cancer in situ (N = 4435), or breast cancer (N = 8512) during 2005-2014 in Skåne, Sweden, were considered as exposed to a breast diagnostic workup. We used multivariable Poisson regression to compare rates of psychiatric disorders and cardiovascular diseases during the 6 weeks before the date of diagnosis of these women with the corresponding rates of women not undergoing such workup. The commonest waiting time for breast cancer patients was 6 weeks during the study period. A within-individual comparison was performed to control for potential unmeasured time-stationary confounders. RESULTS: Compared to the reference, we found a higher rate of psychiatric disorders during the 6 weeks before diagnosis of benign tumor or breast cancer in situ (incidence rate ratio [IRR], 1.3; 95% confidence interval [CI], 1.1 to 1.5) and breast cancer (IRR, 1.4; 95% CI, 1.2 to 1.6). A higher rate was also noted for cardiovascular diseases (IRR, 1.3; 95% CI, 1.1 to 1.6 for benign tumor or breast cancer in situ, and IRR, 1.9; 95% CI, 1.8 to 2.0 for breast cancer). The rate increases for breast cancer were greater comparing a diagnostic workup due to symptoms to a workup due to screening. Little rate increase of neither psychiatric disorders nor cardiovascular diseases was noted during the 6 weeks before the diagnosis of unspecified lump in breast. The within-individual comparison largely confirmed these findings. CONCLUSIONS: Women with benign and malignant breast tumor had increased rates of psychiatric disorders and cardiovascular diseases during the waiting for a final diagnosis.

A diagnosis of rheumatoid arthritis, endometriosis or IBD is associated with later onset of fibromyalgia and chronic widespread pain.

BACKGROUND: Widespread pain is a common comorbidity in several chronic diseases and is suspected to be caused by pain resulting from the underlying disease that has provoked a state of central sensitization. However, this argument is currently limited by evidence that has insufficiently captured the temporal nature of the relationship between diagnosis of the underlying disease and onset of widespread pain. The aim of this study was to investigate if patients with rheumatoid arthritis (RA), endometriosis or inflammatory bowel disease (IBD), have a higher risk of developing widespread pain (fibromyalgia or chronic widespread pain [CWP]). METHODS: Using the Swedish Skåne Healthcare register on health care consultation, a cohort of 889,938 adult patients were followed from 2007 to 2016 and incident cases of RA, endometriosis or IBD and of fibromyalgia and CWP were identified by registered diagnoses. Using Poisson regression, we calculated incidence rate ratios (IRR) adjusted for sex, age, education and propensity to seek health care. RESULTS: For patients with RA the IRR for later fibromyalgia was 3.64 (95% CI: 2.75-4.81) compared to patients without RA, for CWP it was 2.96 (95% CI: 1.81-4.86). For endometriosis patients the IRR for fibromyalgia was 2.83 (95% CI: 1.96-4.08) and for CWP 5.02 (95% CI: 3.10-8.13). IBD patients had an IRR = 2.32 (95% CI: 1.58-3.42) for fibromyalgia and 1.42 (95% CI: 0.93-2.17) for CWP. CONCLUSIONS: This study shows that RA, endometriosis and IBD are all risk factors for later fibromyalgia and CWP, consistent with a hypothesis of central sensitization as an effect of a painful underlying condition. SIGNIFICANCE: We show that RA, endometriosis and IBD predisposes for later fibromyalgia and CWP, a common hypothesis previously difficult to verify due to lack of longitudinal data. The results inform further research regarding the aetiology of fibromyalgia and CWP and stress the need of clinical focus on the pain itself in chronic diseases with pain as a symptom.

Income disparities in healthcare use remain after controlling for healthcare need: evidence from Swedish register data on psoriasis and psoriatic arthritis.

We used a southern Swedish cohort of psoriasis (PSO) and psoriatic arthritis (PsA) patients and population-based referents (N = 57,800) to investigate the influence of socioeconomic and demographic factors on the probability of healthcare use and on healthcare costs when controlling for need as measured by PSO/PsA and common additional morbidities such as diabetes, depression and myocardial infarction. People with PSO/PsA were identified by ICD-10 codes in the Skåne Healthcare Register 1998-2007. Resource use and costs for years 2008-2011 were retrieved from the Skåne Healthcare Register and the Swedish Prescribed Drug Register, and socioeconomic data were retrieved from Statistics Sweden. After controlling for PSO/PsA and common additional morbidities, income, and to some extent education, had significant effects on the probability of five types of healthcare use. Overall, income showed a bell-shaped relationship to healthcare costs, with patients in income quintiles 2 and 3 having the highest mean annualized cost irrespective of model specification. Education did not have a significant effect in most specifications. Analyses including interaction effects indicated similarly higher costs across income quintiles in the PSO and PsA subgroups, though these cost differences were lower in magnitude for patients with PSO in quintile 5 and with PsA in quintile 1. In conclusion, our results show persistent socioeconomic disparities in healthcare use among a cohort of chronically ill patients and referents, even after controlling for the presence of PSO/PsA and common additional morbidities. These disparities persist even in a country with general healthcare coverage and low out-of-pocket payments.

Secular trends in sickness absence among Swedish patients with ankylosing spondylitis and psoriatic arthritis.

The aim was to investigate whether secular trends in sickness absence (SA) were present in patients with ankylosing spondylitis (AS) and psoriatic arthritis (PsA) receiving their diagnosis between 2002 and 2011. A repeated cross-sectional study design was used. Patients were identified in the Skåne Healthcare Register (SHR). A washout period of 18 months was applied. The general population seeking health care was used as a reference cohort. SA data from 2003 to 2012 were obtained from the Swedish Social Insurance Agency and converted into net days of SA per year. Within diagnosis and sex, the average number of net days of SA during the calendar year following diagnosis was calculated and plotted against calendar year together with the corresponding SA of the age-standardized reference population. Linear regression on aggregated data, within diagnosis and sex, was applied to formally investigate differences in secular trends among patients and referents. There were 3173 patients and 992,502 referents. Among men diagnosed with AS, the average amount of SA declined by 8.1 net days per year in patients as compared with 2.4 in the referents (p = 0.01). Among PsA patients, the average amount of SA declined by 11.7 net days per year in women as compared with 2.7 in the referents (p < 0.001) and by 7.6 net days per year in men as compared with 1.9 in the referents (p < 0.001). Secular trends of declining SA were present among AS and PsA patients. Trends were also present among the referents, although not at all of the same magnitude.

Work disability in non-radiographic axial spondyloarthritis patients before and after start of anti-TNF therapy: a population-based regional cohort study from southern Sweden.

Objective: The aim was to assess work-loss days before and after commencement of anti-TNF treatment in patients with non-radiographic axial spondylarthritis (nr-axSpA). Methods: Bionaïve nr-axSpA patients (n = 75), aged 17-62 years, fulfilling the Assessment of SpondyloArthritis international Society criteria for axial spondyloarthritis and starting anti-TNF treatment during 2004-11, were retrieved from the observational South Swedish Arthritis Treatment Group study. Patient information was linked to Swedish Social Insurance Agency data on sick leave and disability pension from 1 year before to 2 years after anti-TNF initiation. Matched population references were included for comparison and to adjust for secular trends. Results: The nr-axSpA patients had a median age of 35 years and disease duration of 6 years at the start of treatment. During the 2 years after anti-TNF initiation, mean work-loss days (including both sick leave and disability pension) in the nr-axSpA group decreased significantly from 3.4 to 1.9 times more than among the population references. The effect was seen on sick leave, whereas disability pension levels remained similar in both groups throughout. Conclusion: Anti-TNF therapy in nr-axSpA was associated with a significant and sustained improvement of work disability over 2 years. However, the proportion of work-loss days remained almost twice as high as in the general population at the end of follow-up.

Injuries before and after diagnosis of cancer: nationwide register based study.

OBJECTIVE:  To examine the relative risks of iatrogenic and non-iatrogenic injuries during the period shortly before and after a diagnosis of cancer. DESIGN:  Nationwide register based study. SETTING:  Swedish national population and health registers. PARTICIPANTS:  720 901 patients with diagnosis of cancer, 1991-2009, in Sweden. MAIN OUTCOME MEASURES:  All hospital admissions in patients with cancer with a main discharge diagnosis of iatrogenic (from medical complications) or non-iatrogenic injuries in 1990-2010 identified from the Swedish patient register. Conditional Poisson regression was used to compare the incidence rate of injuries during the "diagnostic period" (16 weeks before to 16 weeks after diagnosis) with the incidence rate during a "pre-diagnostic period" (the same 32 weeks one year before diagnosis) among the same patients. RESULTS:  During the diagnostic period, there were 7306 iatrogenic (incidence rate 0.60 per 1000 person months) and 8331 non-iatrogenic injuries (incidence rate 0.69 per 1000 person months). For iatrogenic injuries, the incidence rate ratio was 7.0 (95% confidence interval 6.6 to 7.4) during the diagnostic period compared with the pre-diagnostic period. The increase in risk started two weeks before cancer diagnosis and peaked during the two weeks after diagnosis (48.6, 37.3 to 63.5). For non-iatrogenic injuries, the incidence rate ratio was 1.9 (1.8 to 2.0) during the diagnostic period compared with the pre-diagnostic period. The increase in risk began four weeks before diagnosis and peaked during the two weeks before diagnosis (5.3, 4.6 to 6.1). There were increased risks of both types of injury during the diagnostic period for all common cancers, with the smallest risk increase noted for non-melanoma skin cancer. CONCLUSIONS:  Patients with cancer have highly increased risks of both iatrogenic and non-iatrogenic injuries requiring inpatient care : shortly before and after their diagnosis. These findings shed further light on the total burden of medical complications and call for prevention of intentional and unintentional injuries during the diagnostic process of cancer.

Sickness absence from work among persons with new physician-diagnosed carpal tunnel syndrome: a population-based matched-cohort study.

BACKGROUND: Carpal tunnel syndrome is common among employed persons. Data on sickness absence from work in relation to carpal tunnel syndrome have been usually based on self-report and derived from clinical or occupational populations. We aimed to determine sickness absence among persons with physician-diagnosed carpal tunnel syndrome as compared to the general population. METHODS: In Skåne region in Sweden we identified all subjects, aged 17-57 years, with new physician-made diagnosis of carpal tunnel syndrome during 5 years (2004-2008). For each subject we randomly sampled, from the general population, 4 matched reference subjects without carpal tunnel syndrome; the two cohorts comprised 5456 and 21,667 subjects, respectively (73% women; mean age 43 years). We retrieved social insurance register data on all sickness absence periods longer than 2 weeks from 12 months before to 24 months after diagnosis. Of those with carpal tunnel syndrome 2111 women (53%) and 710 men (48%) underwent surgery within 24 months of diagnosis. We compared all-cause sickness absence and analyzed sickness absence in conjunction with diagnosis and surgery. RESULTS: Mean number of all-cause sickness absence days per each 30-day period from 12 months before to 24 months after diagnosis was significantly higher in the carpal tunnel syndrome than in the reference cohort. A new sickness absence period longer than 2 weeks in conjunction with diagnosis was recorded in 12% of the women (n = 492) and 11% of the men (n = 170) and with surgery in 53% (n = 1121) and 58% (n = 408) of the surgically treated, respectively; median duration in conjunction with surgery was 35 days (IQR 27-45) for women and 41 days (IQR 28-50) for men. CONCLUSIONS: Persons with physician-diagnosed carpal tunnel syndrome have substantially more sickness absence from work than age and sex-matched persons from the general population from 1 year before to 2 years after diagnosis. Gender differences were small.

Promoting work ability in a structured national rehabilitation program in patients with musculoskeletal disorders: outcomes and predictors in a prospective cohort study.

BACKGROUND: Musculoskeletal disorders (MSDs) are a major reason for impaired work productivity and sick leave. In 2009, a national rehabilitation program was introduced in Sweden to promote work ability, and patients with MSDs were offered multimodal rehabilitation. The aim of this study was to analyse the effect of this program on health related quality of life, function, sick leave and work ability. METHODS: We conducted a prospective, observational cohort study including 406 patients with MSDs attending multimodal rehabilitation. Changes over time and differences between groups were analysed concerning function, health related quality of life, work ability and sick leave. Regression analyses were used to study the outcome variables health related quality of life (measured with EQ-5D), and sick leave. RESULTS: Functional ability and health related quality of life improved after rehabilitation. Patients with no sick leave/disability pension the year before rehabilitation, improved health related quality of life more than patients with sick leave/disability pension the year before rehabilitation (p = 0.044). During a period of -/+ four months from rehabilitation start, patients with EQ-5D ≥ 0.5 at rehabilitation start, reduced their net sick leave days with 0.5 days and patients with EQ-5D <0.5 at rehabilitation start, increased net sick leave days with 1.5 days (p = 0.019). Factors negatively associated with sick leave at follow-up were earlier episodes of sick leave/disability pension, problems with exercise tolerance functions and mobility after rehabilitation. Higher age was associated with not being on sick leave at follow-up and reaching an EQ-5D ≥ 0.5 at follow-up. Severe pain after rehabilitation, problems with exercise tolerance functions, born outside of Sweden and full-time sick leave/disability pension the year before rehabilitation were all associated with an EQ-5D level < 0.5 at follow-up. CONCLUSIONS: Patients with MSDs participating in a national work promoting rehabilitation program significantly improved their health related quality of life and functional ability, especially those with no sick leave. This shows that vocational rehabilitation programs in a primary health care setting are effective. The findings of this study can also be valuable for more appropriate patient selection for rehabilitation programs for MSDs.

Sick leave in patients with ankylosing spondylitis before and after anti-TNF therapy: a population-based cohort study.

OBJECTIVE: To study levels of sick leave and disability pension before and after TNF-antagonist therapy in AS patients. METHODS: Using the population-based South Swedish Arthritis Treatment Group register, we identified 139 AS patients (aged 18-58 years, 78% men), who between January 2002 and December 2008 started their first treatment with adalimumab, etanercept or infliximab. We linked data to the payment register by the Swedish Social Insurance Agency and calculated the proportion on sick leave in 30-day intervals from 12 months before treatment start until 12 months after. For each AS patient, we randomly selected four subjects from the general population matched for age, sex and area of residence. RESULTS: One to 3 months before treatment, an average of 24% of AS patients were on sick leave. During the first 6 months after treatment start, this fraction dropped to 15%, and further declined to 12% at 12 months (P < 0.001). Comparing AS patients with the general population, the relative risk of being on sick leave 3 months before treatment, treatment start and 12 months after treatment start was 8.0 (95% CI 4.6, 13.9), 9.2 (95% CI 5.4, 15.7) and 4.0 (95% CI 2.1, 6.3), respectively. The decrease in sick leave was not substantially offset by changes in disability pension. CONCLUSION: There is a decline in sick leave during the first 12 months after initiation of TNF-antagonist treatment in AS patients not explained by societal factors or secular trends. The proportion of AS patients on disability pension remained unchanged during the observation period.

Decrease in sick leave among patients with rheumatoid arthritis in the first 12 months after start of treatment with tumour necrosis factor antagonists: a population-based controlled cohort study.

OBJECTIVE: To investigate the effect of tumour necrosis factor (TNF) antagonist treatment of patients with rheumatoid arthritis (RA) on sick leave (SL) and disability pension (DP) in a population-based setting in southern Sweden. METHODS: All patients with RA in the South Swedish Arthritis Treatment Group register living in the county of Skåne (population 1.2 million), who started their first treatment with a TNF antagonist between January 2004 and December 2007 and were 18-58 years at treatment start (n = 365), were identified. For each patient with RA, four matched reference subjects from the general population were randomly selected. Data were linked to the Swedish Social Insurance Agency register and the point prevalence of SL and DP as well as days of SL and DP per month were calculated from 360 days before until 360 days after treatment start. RESULTS: At treatment start 38.6% of the patients with RA were registered for SL. During the first 6 months this share dropped to 28.5% (decrease by 26.2%, p< 0.001). This level remained stable throughout the first treatment year. Comparing patients with RA to the reference group the relative risk of being on SL was 6.6 (95% CI 5.2 to 8.5) at initiation of anti-TNF treatment and 5.2 (95% CI 4.0 to 6.8) 1 year after that. The corresponding figures for DP were 3.4 (95% CI 2.7 to 4.2) and 3.2 (95% CI 2.7 to 3.9). CONCLUSIONS: There was a marked decline in SL during the first 6 months of TNF antagonist treatment in patients with RA in southern Sweden, maintained throughout the first year, which was not offset by a corresponding increase in DP.