Burden of disease and management of osteoarthritis and chronic low back pain: healthcare utilization and sick leave in Sweden, Norway, Finland and Denmark (BISCUITS): study design and patient characteristics of a real world data study.

OBJECTIVES: Osteoarthritis (OA) and chronic low back pain (CLBP) are common musculoskeletal disorders with substantial patient and societal burden. Nordic administrative registers offer a unique opportunity to study the impact of these conditions in the real-world setting. The Burden of Disease and Management of Osteoarthritis and Chronic Low Back Pain: Health Care Utilization and Sick Leave in Sweden, Norway, Finland and Denmark (BISCUITS) study was designed to study disease prevalence and the societal and economic burden in broad OA and CLBP populations. METHODS: Patients in Sweden, Norway, Finland and Denmark with diagnoses of OA or CLBP (low back pain record plus ≥2 pain relief prescriptions to indicate chronicity) were identified in specialty care, in primary care (Sweden and Finland) and in a quality-of-care register (Sweden). Matched controls were identified for the specialty care cohort. Longitudinal data were extracted on prevalence, treatment patterns, patient-reported outcomes, social and economic burden. RESULTS: Almost 1.4 million patients with OA and 0.4 million with CLBP were identified in specialty care, corresponding to a prevalence in the Nordic countries of 6.3 and 1.9%, respectively. The prevalence increased to 11-14% for OA and almost 6% for CLBP when adding patients identified in primary care. OA patients had a higher Elixhauser comorbidity index (0.66 vs. 0.46) and were using opioids (44.7 vs. 10.2%) or long-term nonsteroidal anti-inflammatory drug (NSAIDs) (20.9 vs. 4.5%) more than four times as often as compared to controls. The differences were even larger for CLBP patients compared to their controls (comorbidity index 0.89 vs. 0.39, opioid use 77.7 vs. 9.4%, and long-term NSAID use 37.2 vs. 4.8%). CONCLUSIONS: The BISCUITS study offers an unprecedented, longitudinal healthcare data source to quantify the real-world burden of more than 1.8 million patients with OA or CLBP across four countries. In subsequent papers we aim to explore among others additional outcomes and subgroups of patients, primarily those patients who may benefit most from better healthcare management.

Predictors of Sickness Absence in a Clinical Population With Chronic Pain.

Chronic pain-related sickness absence is an enormous socioeconomic burden globally. Optimized interventions are reliant on a lucid understanding of the distribution of social insurance benefits and their predictors. This register-based observational study analyzed data for a 7-year period from a population-representative sample of 44,241 chronic pain patients eligible for interdisciplinary treatment (IDT) at specialist clinics. Sequence analysis was used to describe the sickness absence over the complete period and to separate the patients into subgroups based on their social insurance benefits over the final 2 years. The predictive performance of features from various domains was then explored with machine learning-based modeling in a nested cross-validation procedure. Our results showed that patients on sickness absence increased from 17% 5 years before to 48% at the time of the IDT assessment, and then decreased to 38% at the end of follow-up. Patients were divided into 3 classes characterized by low sickness absence, sick leave, and disability pension, with eight predictors of class membership being identified. Sickness absence history was the strongest predictor of future sickness absence, while other predictors included a 2008 policy, age, confidence in recovery, and geographical location. Information on these features could guide personalized intervention in the specialized healthcare. PERSPECTIVE: This study describes sickness absence in patients who visited a Swedish pain specialist interdisciplinary treatment clinic during the period 2005 to 2016. Predictors of future sickness absence are also identified that should be considered when adapting IDT programs to the patient's needs.

Predictive validity of general work ability assessments in the context of sickness insurance.

OBJECTIVE: The activity ability assessment is a Swedish method for assessing general work ability, based on self-reports combined with an examination by specially trained physicians, and, if needed, extended assessments by occupational therapists, physiotherapists and/or psychologists. The aim of this study was to analyse the predictive validity of the activity ability assessment in relation to future sick leave. DESIGN: Analysis of assessments in 300 case files, in relation to register data on sick leave. SUBJECTS: People on sick leave (n =300, 32% men, 68% women; mean age 48 years; assessment at mean sick leave day 249). METHODS: Univariate and multivariate statistics. RESULTS: Self-rated work ability was the only factor with predictive value related to future sick leave. Physicians' evaluations lacked predictive value, except where the person had a limitation in vision, hearing or speech that was predictive of future decisions by the Social Insurance Agency. No sex differences were identified. CONCLUSION: The predictive value of the activity ability assessment for future sick leave is limited, and self-rated work ability is more accurate compared with an extensive insurance medical assessment. Self-rated work ability may be more holistic compared with insurance medicine assessments, which may be overly focused on individual factors. A practical implication of this is that the inclusion of contextual factors in assessment procedures needs to be improved.

A cost-utility analysis of multimodal pain rehabilitation in primary healthcare.

OBJECTIVES: Multimodal rehabilitation programs (MMRPs) have been shown to be both cost-effective and an effective method for managing chronic pain in specialist care. However, while the vast majority of patients are treated in primary healthcare, MMRPs are rarely practiced in these settings. Limited time and resources for everyday activities alongside the complexity of chronic pain makes the management of chronic pain challenging in primary healthcare and the focus is on unimodal treatment. In order to increase the use of MMRPs incentives such as cost savings and improved health status in the patient group are needed. The aim of this study was to evaluate the cost-effectiveness of MMRPs for patients with chronic pain in primary healthcare in two Swedish regions. The aim of this study was to evaluate the cost-effectiveness of MMRPs at one-year follow-up in comparison with care as usual for patients with chronic pain in primary healthcare in two Swedish regions. METHODS: A cost-utility analysis was performed alongside a prospective cohort study comparing the MMRP with the alternative of continuing with care as usual. The health-related quality of life (HRQoL), using EQ5D, and working situation of 234 participants were assessed at baseline and one-year follow-up. The primary outcome was cost per quality-adjusted life year (QALY) gained while the secondary outcome was sickness absence. An extrapolation of costs was performed based on previous long-term studies in order to evaluate the effects of the MMRP over a five-year time period. RESULTS: The mean (SD) EQ5D index, which measures HRQoL, increased significantly (p<0.001) from 0.34 (0.32) to 0.44 (0.32) at one-year follow-up. Sickness absence decreased by 15%. The cost-utility analysis showed a cost per QALY gained of 18 704 € at one-year follow-up. CONCLUSIONS: The results indicate that the MMRP significantly improves the HRQoL of the participants and is a cost-effective treatment for patients with chronic pain in primary healthcare when a newly suggested cost-effectiveness threshold of 19 734 € is implemented. The extrapolation indicates that considerable cost savings in terms of reduced loss of production and gained QALYs may be generated if the effects of the MMRP are maintained beyond one-year follow-up. The study demonstrates potential benefits of MMRPs in primary healthcare for both the patient with chronic pain and the society as a whole. The cost-effectiveness of MMRPs in primary healthcare has scarcely been studied and further long-term studies are needed in these settings.

Elaborating on the assessment of the risk of bias in prognostic studies in pain rehabilitation using QUIPS-aspects of interrater agreement.

BACKGROUND: Many studies have been performed to identify important prognostic factors for outcomes after rehabilitation of patients with chronic pain, and there is a need to synthesize them through systematic review. In this process, it is important to assess the study quality and risk of bias. The "Quality In Prognosis Studies" (QUIPS) tool has been developed for this purpose and consists of several prompting items categorized into six domains, and each domain is judged on a three-grade scale (low, moderate or high risk of bias). The aim of the present study was to determine the interrater agreement of the risk of bias assessment in prognostic studies of patients with chronic pain using QUIPS and to elaborate on the use of this instrument. METHODS: We performed a systematic review and a meta-analysis of prognostic factors for long-term outcomes after multidisciplinary rehabilitation in patients with chronic pain. Two researchers rated the risk of bias in 43 published papers in two rounds (15 and 28 papers, respectively). The interrater agreement and Cohen's quadratic weighted kappa coefficient (κ) and 95% confidence interval (95%CI) were calculated in all domains and separately for the first and second rounds. RESULTS: The raters agreed in 61% of the domains (157 out of 258), with similar interrater agreement in the first (59%, 53/90) and second rounds (62%, 104/168). The overall weighted kappa coefficient (kappa for all domains and all papers) was weak: κ = 0.475 (95%CI = 0.358-0.601). A "minimal agreement" between the raters was found in the first round, κ = 0.323 (95%CI = 0.129-0.517), but increased to "weak agreement" in the second round, κ = 0.536 (95%CI = 0.390-0.682). CONCLUSION: Despite a relatively low interrater agreement, QUIPS proved to be a useful tool in assessing the risk of bias when performing a meta-analysis of prognostic studies in pain rehabilitation, since it demands of raters to discuss and investigate important aspects of study quality. Some items were particularly hard to differentiate in-between, and a learning phase was required to increase the interrater agreement. This paper highlights several aspects of the tool that should be kept in mind when rating the risk of bias in prognostic studies, and provides some suggestions on common pitfalls to avoid during this process. TRIAL REGISTRATION: PROSPERO CRD42016025339; registered 05 February 2016.

Fair or square? Experiences of introducing a new method for assessing general work ability in a sickness insurance context.

PURPOSE: To study social validity and perceived fairness of a new method for assessing general work ability in a sickness insurance context. Assessments are based on self-reports, combined with examinations by physicians, and, if needed, occupational therapists, physiotherapists and/or psychologists. MATERIALS AND METHODS: Interviews with 36 insurance officials, 10 physicians, and 36 sick-listed persons, which were analysed through a qualitative content analysis. RESULTS: Insurance officials and physicians considered the method useful and that it facilitated benefit decisions. The experiences of persons who had undergone the assessment differed, where the dialog with insurance officials seemed to have had an influence on experiences of the assessment and the decisions it led to. CONCLUSIONS: The perceived fairness and social validity of the assessment depended on how it was carried out; organisational conditions and priorities; communication skills; and decision outcomes. Professionals have an important pedagogical task in explaining the purpose and procedure of the assessment in order for the sick-listed to perceive it as fair rather than square, i.e., too standardised and not considering individual conditions. If the assessment could be used also for rehabilitative purposes, it could possibly be perceived as more acceptable also in cases where it leads to denied benefits. Implications for rehabilitation The perceived fairness of work ability assessments is dependent on procedures for the assessment, communication with the person, and the outcome. What is considered fair differs between assessing professionals and persons being assessed. Professionals may influence the perceptions of fairness through their way of communication. Assessments need to be coupled with rehabilitation measures in order to perceived as relevant and acceptable.

People in states worse than dead according to the EQ-5D UK value set: would they rather be dead?

PURPOSE: Quality-adjusted life years (QALYs) measure health by combining length and quality of life. QALYs constitute the effect side of incremental cost-effectiveness ratios, describing the results of health economic evaluations. The objectives of this study were to (1) investigate the prevalence of states worse than dead (SWD) when using the EuroQol-5D UK value set, and (2) to study to what extent SWDs are reasonable with a starting point in experience-based valuations of health states. METHODS: Data from a Swedish cross-sectional population survey were used. The survey was directed to 10,000 persons 65 years and older and its primary aim was to investigate the prevalence and consequences of chronic pain. The survey included questions reflecting life situation and well-being. Some of these were used in order to characterise people in SWD. RESULTS: SWD were found in 1.8% of the 6611 respondents. The prevalence of SWD increased with advancing age and was more common among women than men. The control questions used indicated that most of the persons being in SWD according to the EQ-5D UK value set most probably would not judge themselves to be in a SWD. CONCLUSIONS: Though negative QALY-weights are not very common, they constitute a non-negligible part of health states in a Swedish population 65 years and older. Prevalence of SWD is higher among women than men and increases with age. From responses to other questions on well-being and life situation, there is reason to doubt the reasonableness of experience-based negative QALY-weights in many cases.

Distinctive subgroups derived by cluster analysis based on pain and psychological symptoms in Swedish older adults with chronic pain - a population study (PainS65+).

BACKGROUND: Improved knowledge based on clinical features of chronic pain in older adults would be valuable in terms of patient-orientated approaches and would provide support for health care systems in optimizing health care resources. This study identifies subgroups based on pain and psychological symptoms among Swedish older adults in the general population and compares derived subgroups with respect to socio-demographics, health aspects, and health care costs. METHODS: This cross-sectional study uses data collected from four registers and one survey. The total sample comprised 2415 individuals ≥65 years old. A two-step cluster analysis was performed. Data on pain intensity, number of pain sites, anxiety, depression, and pain catastrophizing were used as classification variables. Differences in socio-demographics, quality of life, general health, insomnia, and health care costs among the clusters were investigated. Association of the clusters with the above parameters was further evaluated using multinomial logistic regression. RESULTS: Four major clusters were identified: Subgroup 1 (n = 325; 15%) - moderate pain and high psychological symptoms; Subgroup 2 (n = 516; 22%) - high pain and moderate psychological symptoms; Subgroup 3 (n = 686; 30%) - low pain and moderate psychological symptoms; and Subgroup 4 (n = 767; 33%) - low pain and low psychological symptoms. Significant differences were found between the four clusters with regard to age, sex, educational level, family status, quality of life, general health, insomnia, and health care costs. The multinomial logistic regression analysis revealed that Subgroups 1 and 2, compared to Subgroup 4, were significantly associated with decreased quality of life, decreased general health, and increased insomnia. Subgroup 3, compared to Subgroup 4, was associated with decreased general health and increased insomnia. In addition, compared to Subgroup 4, Subgroups 1 and 2 were significantly associated with higher health care costs. CONCLUSIONS: Two high risk clusters of older adults suffering from chronic pain; one mainly based on psychological symptoms and one mainly on pain intensity and pain spread, associated with decreased quality of life and health and increased health care costs were identified. Our findings indicate that subgroup-specific treatment will improve pain management and reduce health care costs.

Comorbidities, intensity, frequency and duration of pain, daily functioning and health care seeking in local, regional, and widespread pain - a descriptive population-based survey (SwePain).

BACKGROUND: The clinical knowledge of factors related to the spread of pain on the body has increased and understanding these factors is essential for effective pain treatment. This population-based study examines local (LP), regional (RP), and widespread pain (WSP) on the body regarding comorbidities, pain aspects, and impact of pain and elucidates how the spread of pain varies over time. MATERIAL AND METHODS: A postal questionnaire that addressed pain aspects (intensity, frequency, duration and anatomical spreading on a body manikin), comorbidities and implications of pain (i.e., work situation, physical activity, consumption of health care and experience of hospitality and treatment of health care) was sent to 9000 adults living in southeastern Sweden. Of these, 4774 (53 %) completed and returned the questionnaire. After 9 weeks, a follow-up questionnaire was sent to the 2983 participants who reported pain in the first questionnaire (i.e. 62 % of 4774 subjects). Of these, 1940 completed and returned the questionnaire (i.e. 65 % of 2983 subjects). The follow-up questionnaire included the same items as the first questionnaire. RESULTS: This study found differences in intensity, frequency and duration of pain, comorbidities, aspects of daily functioning and health care seeking in three pain categories based on spreading of pain: LP, RP and WSP. Compared to the participants with RP and LP, the participants with WSP had lower education and worse overall health, including more frequent heart disease and hypertension. In addition, participants with WSP had more intense, frequent, and long-standing pain, required more medical consultations, and experienced more impact on work. The participants with RP constituted an intermediate group regarding frequency and intensity of pain, and impact on work. The participants with LP were the least affected group regarding these factors. A substantial transition to RP had occurred by the 9-week follow-up. CONCLUSIONS: This study shows an association between increased spread of pain and prevalence of heart disease, hypertension, more severe pain characteristics (i.e., intensity, frequency and duration), problems with common daily activities and increased health care seeking. The WSP group was the most affected group and the LP group was the least affected group. Regarding these factors, RP was an obvious intermediate group. The transitions between the pain categories warrant research that broadly investigates factors that increase and decrease pain.

Severity of chronic pain in an elderly population in Sweden--impact on costs and quality of life.

Chronic pain is associated with large societal costs, but few studies have investigated the total costs of chronic pain with respect to elderly subjects. The elderly usually require informal care, care performed by municipalities, and care for chronic diseases, all factors that can result in extensive financial burdens on elderly patients, their families, and the social services provided by the state. This study aims to quantify the societal cost of chronic pain in people of age 65 years and older and to assess the impact of chronic pain on quality of life. This study collected data from 3 registers concerning health care, drugs, and municipal services and from 2 surveys. A postal questionnaire was used to collect data from a stratified sample of the population 65 years and older in southeastern Sweden. The questionnaire addressed pain intensity and quality of life variables (EQ-5D). A second postal questionnaire was used to collect data from relatives of the elderly patients suffering from chronic pain. A total of 66.5% valid responses of the 10,000 subjects was achieved; 76.9% were categorized as having no or mild chronic pain, 18.9% as having moderate chronic pain, and 4.2% as having severe chronic pain. Consumed resources increased with the severity of chronic pain. Clear differences in EQ-5D were found with respect to the severity of pain. This study found an association between resource use and severity of chronic pain in elderly subjects: the more severe the chronic pain, the more extensive (and expensive) the use of resources.

Chronic musculoskeletal pain: review of mechanisms and biochemical biomarkers as assessed by the microdialysis technique.

Chronic musculoskeletal pain conditions are multifaceted, and approximately 20% of the adult population lives with severe chronic pain, with a higher prevalence in women and in lower income groups. Chronic pain is influenced by and interacts with physical, emotional, psychological, and social factors, and a biopsychosocial framework is increasingly applied in clinical practice. However, there is still a lack of assessment procedures based on the activated neurobiological pain mechanisms (ie, the biological part of the biopsychosocial model of pain), which may be a necessary step for further optimizing outcomes after treatments for patients with chronic pain. It has been suggested that chronic pain conditions are mainly driven by alterations in the central nervous system with little or no peripheral stimuli or nociception. In contrast, other authors argue that such central alterations are driven by peripheral alterations and nociceptive input. Microdialysis is an in vivo method for studying local tissue alterations and allows for sampling of substances in the interstitium of the muscle, where nociceptor free nerve endings are found close to the muscle fibers. The extracellular matrix plays a key role in physiologic functions of cells, including the primary afferent nociceptor. The present review mainly concerns the results of microdialysis studies and how they can contribute to the understanding of activated peripheral nociceptive and pain mechanisms in humans with chronic pain. The primary aim was to review molecular studies using microdialysis for the investigation of human chronic muscle pain, ie, chronic masticatory muscle pain, chronic trapezius myalgia, chronic whiplash-associated disorders, and chronic widespread pain/fibromyalgia syndrome. Several studies clearly showed elevated levels of serotonin, glutamate, lactate, and pyruvate in localized chronic myalgias and may be potential biomarkers. These results indicate that peripheral muscle alterations are parts of the activated pain mechanisms in common chronic pain conditions. Muscle alterations have been reported in fibromyalgia syndrome and chronic widespread pain, but more studies are needed before definite conclusions can be drawn. For other substances, results are inconclusive across studies and patient groups.

Construct validity of the Assessment of Work Performance (AWP).

The instrument Assessment of Work Performance (AWP 1.1) can be used to assess an individual's skills during work performance - how efficient and appropriate a client performs a work task. The instrument is currently used by over 300 assessors working in a variety of work rehabilitation settings in Sweden, and it has been used with over 10,000 clients. In this study, the construct validity of the AWP 1.1 was tested with 364 assessments of clients with a variety of various work-related problems assessed by six occupational therapists in a Social Insurance Office in Sweden between 2004 and 2005. Principal Component Analysis shows construct validity of the AWP 1.1. Further, the findings indicate that the instrument is sensitive and discriminates between clients, and no gender related patterns were identified.

Content validity and utility of the Assessment of Work Performance (AWP).

In the area of work rehabilitation, many decisions about future interventions for the client are based on the results of various kinds of assessments. Therefore, it is important that the assessment instruments used are adequate, useful, and reliable. The purpose of this study was to investigate the content validity and utility of the instrument Assessment of Work Performance (AWP) which is used to assess an individual's observable (working) skills during work performance, i.e. how efficient and appropriate a client performs a work activity. A questionnaire was answered by 67 respondents who used the AWP in various work rehabilitation settings in Sweden. The result indicates content validity and utility for the AWP that supports further testing of the instrument.

Hand function and activity limitation according to health assessment questionnaire in patients with rheumatoid arthritis and healthy referents: 5-year followup of predictors of activity limitation (The Swedish TIRA Project).

OBJECTIVE: This study identifies baseline predictors of future activity limitation in rheumatoid arthritis (RA). To reinforce the utility of instruments assessing functional ability/activity limitation, we used reference data from healthy referents. METHODS: This study includes 189 patients (69% women) with recent-onset RA (onset of joint swelling not more than 12 months at diagnosis) in a prospective cohort ("the Swedish TIRA project") during 27 months from 1996 through 1998. Regular followups were done for a period of 5 years, and 123 healthy persons (50% women) were recruited as referents. Hand function was assessed by the "grip ability test (GAT)" and "signals of functional impairment" (SOFI). Grip force was measured with the electronic device Grippit. Activity limitation was assessed with the Swedish version of the Health Assessment Questionnaire (HAQ). RESULTS: Throughout the study and for both sexes, GAT, grip force, SOFI-hand, and HAQ were significantly different for the patients compared to healthy referents. In the healthy referents, HAQ was mainly related to age and GAT, whereas in RA HAQ was most obviously linked to grip force. Five years after diagnosis only 8% of HAQ outcome was explained by the baseline measures: HAQ, grip force, SOFI-lower limb, sex, walking speed, and GAT. CONCLUSION: Our study provides valuable reference data for several functional ability and activity limitation measures. The HAQ score was explained by different variables in healthy referents compared to patients with RA. Five years after diagnosis only 8% of HAQ outcome was explained by the variables assessed at inclusion.

Prevalence of current and chronic pain and their influences upon work and healthcare-seeking: a population study.

OBJECTIVE: To investigate the prevalence of current and chronic pain and their relationship to pain intensity, sex, age, income, employment status, citizenship, marital status, urban residence, occupational activity, and healthcare-seeking based on a representative sample from a Swedish county. METHODS: A cross-sectional survey using a postal questionnaire was sent to a representative sample (n = 9952) of the target population (284,073 people, age 18-74 yrs) in a county (Ostergötland) in southern Sweden. A questionnaire was mailed and followed by 2 postal reminders if necessary. RESULTS: The participation rate was 76.7% (n = 7637); nonparticipants were on average younger, male, and earned less money. The overall point prevalence of pain was 48.9%. The corresponding one-month period prevalence was 63.0%, and pain on several occasions during the previous 3 months was reported by 61.3% of participants. The prevalence of chronic pain (pain > 3 months) was 53.7%. Female sex, age, and sick leave/early retirement were generally of significant importance in the regressions of pain. No sex factor was found in the regressions of pain frequency and pain intensity. Chronic pain especially frequent and intensive pain showed clear associations with healthcare-seeking and occupational activity. CONCLUSION: High prevalence of current pain (48.9%) and chronic pain (53.7%) were found in this community-based study. Being female, older, and on sick leave or early retirement were generally of significant importance in the regressions of pain. Chronic pain showed clear associations with healthcare-seeking and occupational activity, indicating considerable socioeconomic costs.