[Show abstract][Hide abstract] ABSTRACT: The minimal detectable change (MDC) and the minimal clinically important changes (MCIC) have been explored for nonspecific low back pain patients and are similar across different cultural settings. No data on MDC and MCIC for pain severity are available for neck pain patients. The objectives of this study were to estimate MDC and MCIC for pain severity in subacute and chronic neck pain (NP) patients, to assess if MDC and MCIC values are influenced by baseline values and to explore if they are different in the subset of patients reporting referred pain, and in subacute versus chronic patients.
Subacute and chronic patients treated in routine clinical practice of the Spanish National Health Service for neck pain, with or without pain referred to the arm, and a pain severity > or = 3 points on a pain intensity number rating scale (PI-NRS), were included in this study. Patients' own "global perceived effect" over a 3 month period was used as the external criterion. The minimal detectable change (MDC) was estimated by means of the standard error of measurement in patients who self-assess as unchanged. MCIC were estimated by the mean value of change score in patients who self-assess as improved (mean change score, MCS), and by the optimal cutoff point in receiver operating characteristics curves (ROC). The effect on MDC and MCIC of initial scores, duration of pain, and existence of referred pain were assessed.
658 patients were included, 487 of them with referred pain. MDC was 4.0 PI-NRS points for neck pain in the entire sample, 4.2 for neck pain in patients who also had referred pain, and 6.2 for referred pain. MCS was 4.1 and ROC was 1.5 for referred and for neck pain, both in the entire sample and in patients who also complained of referred pain. ROC was lower (0.5 PI-NRS points) for subacute than for chronic patients (1.5 points). MCS was higher for patients with more intense baseline pain, ranging from 2.4 to 4.9 PI-NRS for neck pain and from 2.4 to 5.3 for referred pain.
In general, improvements < or = 1.5 PI-NRS points could be seen as irrelevant. Above that value, the cutoff point for clinical relevance depends on the methods used to estimate MCIC and on the patient's baseline severity of pain. MDC and MCIC values in neck pain patients are similar to those for low back pain and other painful conditions.
[Show abstract][Hide abstract] ABSTRACT: The NDI, COM and NPQ are evaluation instruments for disability due to NP. There was no Spanish version of NDI or COM for which psychometric characteristics were known. The objectives of this study were to translate and culturally adapt the Spanish version of the Neck Disability Index Questionnaire (NDI), and the Core Outcome Measure (COM), to validate its use in Spanish speaking patients with non-specific neck pain (NP), and to compare their psychometric characteristics with those of the Spanish version of the Northwick Pain Questionnaire (NPQ).
Translation/re-translation of the English versions of the NDI and the COM was done blindly and independently by a multidisciplinary team. The study was done in 9 primary care Centers and 12 specialty services from 9 regions in Spain, with 221 acute, subacute and chronic patients who visited their physician for NP: 54 in the pilot phase and 167 in the validation phase. Neck pain (VAS), referred pain (VAS), disability (NDI, COM and NPQ), catastrophizing (CSQ) and quality of life (SF-12) were measured on their first visit and 14 days later. Patients' self-assessment was used as the external criterion for pain and disability. In the pilot phase, patients' understanding of each item in the NDI and COM was assessed, and on day 1 test-retest reliability was estimated by giving a second NDI and COM in which the name of the questionnaires and the order of the items had been changed.
Comprehensibility of NDI and COM were good. Minutes needed to fill out the questionnaires [median, (P25, P75)]: NDI. 4 (2.2, 10.0), COM: 2.1 (1.0, 4.9). Reliability: [ICC, (95%CI)]: NDI: 0.88 (0.80, 0.93). COM: 0.85 (0.75,0.91). Sensitivity to change: Effect size for patients having worsened, not changed and improved between days 1 and 15, according to the external criterion for disability: NDI: -0.24, 0.15, 0.66; NPQ: -0.14, 0.06, 0.67; COM: 0.05, 0.19, 0.92. Validity: Results of NDI, NPQ and COM were consistent with the external criterion for disability, whereas only those from NDI were consistent with the one for pain. Correlations with VAS, CSQ and SF-12 were similar for NDI and NPQ (absolute values between 0.36 and 0.50 on day 1, between 0.38 and 0.70 on day 15), and slightly lower for COM (between 0.36 and 0.48 on day 1, and between 0.33 and 0.61 on day 15). Correlation between NDI and NPQ: r = 0.84 on day 1, r = 0.91 on day 15. Correlation between COM and NPQ: r = 0.63 on day 1, r = 0.71 on day 15.
Although most psychometric characteristics of NDI, NPQ and COM are similar, those from the latter one are worse and its use may lead to patients' evolution seeming more positive than it actually is. NDI seems to be the best instrument for measuring NP-related disability, since its results are the most consistent with patient's assessment of their own clinical status and evolution. It takes two more minutes to answer the NDI than to answer the COM, but it can be reliably filled out by the patient without assistance.
Clinical Trials Register NCT00349544.
[Show abstract][Hide abstract] ABSTRACT: Prospective cohort follow-up study.
To refine the indication criteria for neuroreflexotherapy (NRT) in the treatment of subacute and chronic neck (NP), thoracic (TP) and low back pain (LBP) in the Spanish National Health Service (SNHS), by identifying prognostic factors for clinical outcome.
NRT consists of the temporary subcutaneous implantation of surgical devices in trigger points. Previous randomized controlled trials have shown its efficacy, effectiveness, and cost-effectiveness for treating subacute and chronic LBP. Clinical audits in routine practice have shown similar results in NP, TP, and LBP patients.
All 1514 patients from the SNHS in the Balearic Islands in which a NRT intervention was performed and who were discharged between January 1, 2004, and December 31, 2005, were included in this study. Treatment failure was defined as a baseline score equivalent to or lower than the corresponding one at discharge for local pain, referred pain, or LBP-related disability. Multivariate logistic regression models were developed for each of those variables. Maximal models included reason for referral (NP, TP, or LBP), age, sex, baseline values for each variable, number of days in which the surgical devices used in NRT were left implanted, duration of the current episode, time elapsed since the first episode, and previous failed surgery for the current episode. Calibration of the models was assessed through the Hosmer-Lemeshow test, while discrimination was assessed through the area under the ROC curve and the Nagelkerke R test.
When referred to NRT, patients' median (IQR) duration of the episode was 210 (90, 730) days. Failure rates ranged between 9.9% for local pain and 14.5% for disability. Variables associated with a worst prognosis for local pain, referred pain, and disability were surgical devices remaining implanted for a shorter duration and, especially, a longer pain duration. Patients referred for NP were more likely to improve than those referred for TP or LBP. Regarding the evolution of local and referred pain, lesser improvement was observed in the least severe complaint at baseline. Models showed a good calibration. The area under the ROC curve ranged between 0.719 and 0.804, and R ranged between 0.101 and 0.255.
A longer duration of the current episode is the worst detected prognostic factor for response to NRT, but prognostic models are inaccurate for predicting the clinical outcome of a given patient. In order to improve the success rate of this technology, these results only support earlier referral for patients complying with current indication criteria.