Non-specific low back pain in primary care in the Spanish National Health Service: a prospective study on clinical outcomes and determinants of management

Abstract

BackgroundThe Spanish National Health Service is a universal and free health care system. Non-specific low back pain (LBP) is a prevalent disorder, generating large health and social costs. The objectives of this study were to describe its management in primary care, to assess patient characteristics that influence physicians' decisions, and to describe clinical outcome at 2 months.MethodsA cross-sectional sample of 648 patients with non-specific low back pain was recruited by 75 physicians (out of 361 – 20.8%) working in 40 primary care centers in 10 of the 17 administrative regions in Spain, covering 693,026 out of the 40,499,792 inhabitants. Patients were assessed on the day they were recruited, and prospectively followed-up 14 and 60 days later. The principal patient characteristics that were analyzed were: sex, duration of the episode, history of LBP, working status, severity of LBP, leg pain and disability, and results of straight leg raising test. Descriptors of management were: performance of the straight leg raising test, ordering of diagnostic procedures, prescription of drug treatment, referral to physical therapy, rehabilitation or surgery, and granting of sick leave. Regression analysis was used to analyze the relationship between patients' baseline characteristics and physicians' management decisions. Only workers were included in the models on sick leave.ResultsMean age (SD) of included patients was 46.5 (15.5) years, 367 (56.6%) were workers, and 338 (52.5%) were females. Median (25th–75th interquartile range) duration of pain when entering the study was 4 (2–10) days and only 28 patients (4.3%) had chronic low back pain. Diagnostic studies included plain radiographs in 43.1% of patients and CT or MRI scans in 18.8%. Drug medication was prescribed to 91.7% of patients, 19.1% were sent to physical therapy or rehabilitation, and 9.6% were referred to surgery. The main determinants of the clinical management were duration of the episode and, to a lesser extent, the intensity of the pain (especially leg pain), a positive straight leg raising test, and degree of disability. The main determinant of sick leave was the degree of disability, followed by the characteristics of the labor contract and the intensity of leg pain (but not low back pain). After at least 2 months of treatment, 37% of patients were still in pain and approximately 10% of patients had not improved or had worsened.ConclusionAlthough the use of X-Rays is high, determinants of physicians' management of LBP in primary care made clinical sense and were consistent with patterns suggested by evidence-based recommendations. However, after 2 months of treatment more than one third of patients continued to have back pain and about 10% had worsened.

The prognostic value of catastrophizing for predicting the clinical evolution of low back pain patients: a study in routine clinical practice within the Spanish National Health Service

“…However, LBP-related clinical practice is roughly consistent within the SNHS, and it generally follows current evidence-based guidelines. 36,51,52 The seven Spanish regions in which this study was conducted represent most of the economic and cultural spectrum of the country. Acute (41.9%) and chronic (58.1%) patients were recruited in routine clinical practice, in primary and specialty centers belonging to or working for the SNHS.…”

“…The SNHS is a tax-funded public organization in which all health care services are provided free to every resident in Spain (except aesthetic surgery and some dental procedures). 36 Only a small minority of patients in the upper economic class seek health care exclusively through private health care. Low rates of included patients among those screened, losses to follow-up and missing data, may introduce a risk of bias.…”

“…57,58 Therefore, in this study follow-up was planned at 3 months to ensure that all patients who were still symptomatic at the follow-up assessment would be chronic, 45 and to minimize the risk of losses associated with longer follow-up periods within the routine clinical practice of the SNHS. 36 However, since baseline catastrophizing does not predict the clinical evolution of pain or disability during the first three months, it is not likely for it to become relevant at a later stage. In fact, the prognosis of chronic low back pain is determined by changes in pain and disability occurring in the initial period.…”

“…Therefore, as opposed to randomized clinical trials, there were no ethical reasons for keeping the sample size as small as possible. As a result, sample size for this study was established at 1,500, in order to ensure enough statistical power, given that: a) previous studies had suggested that the potential effect of catastrophizing in Spanish subjects could be small, 10,11,16 b) approximately 80% of LBP patients treated in routine practice within the Spanish National Health Service, report a clinically relevant improvement at 3 months, 36,37 and previous studies have shown that improvements are not normally distributed, 36,38 which excludes linear regression analysis and implies the need to dichotomize continuous variables for logistic regression analyses, which in turn may reduce statistical power, d) this sample size would allow the introduction of up to 30 variables in the regression models as potential confounders. 39 …”

Factors accounting for psychosocial functioning in patients with low back pain

“…In some cases (up to 10-47%), LBP is characterized by a chronic course, and treatment outcomes are not always satisfactory, which for many makes adjusting to living with LBP a challenge [23]. Increased rates of psychological disturbances were reported in previous studies as indices of difficulties in adjustment to LBP.…”