Original Articles“INTERMED”: a method to assess health service needs: II. Results on its validity and clinical use
Introduction
The INTERMED has been developed to integrate, in a standardized manner, the biopsychosocial aspects of disease with the organization of the health care system in an increasingly complex care delivery system 1, 2, 3. The documentation system is conceived for clinical (assessment of case complexity and health care needs), scientific (case mix description; stratification of populations in controlled trials), educational (problem-oriented teaching), and health care policy purposes (quality management). During its conceptualization and development, the face validity of its clinical variables have been extensively discussed among an international group of general hospital psychiatrists [4] and their colleagues from internal medicine, rheumatology, and palliative care. In a first study, the reliability of INTERMED has been evaluated by double scoring a series of patients [1]. In the present paper, the evaluation of the validity and clinical use of the INTERMED in a population with varying degrees of case complexity is reported.
Due to an increasing incidence of patients with benign low back pain in industrialized countries over the last decades [5] and the economic impact that a small minority with chronification and disability represents [6], major efforts have been undertaken to investigate this patient population. Meanwhile, it is well established that a clear correlation among biological variables, medical interventions, and course of disease is lacking 7, 8; that psychosocial factors play an important role, especially in those patients who become disabled 9, 10; and that combined medical and psychosocial interventions are more successful than medical interventions alone 11, 12. The impressive amount of knowledge about risk factors for low back pain disability related to biological [13], psychological 9, 10, sociodemographic [14], and social aspects [15] of the individual, as well as related to the medical [16], legal [17], and socioeconomic and sociocultural system [18] stresses that this patient population—especially the chronified and disabeled—is most adequately described in terms of co-morbidity and case complexity. These patients clearly vary on biological, psychological, and social variables and their medical care utilization. Low back pain patients therefore represent a suitable population to evaluate the validity of the INTERMED. If it is possible to distinguish clinically meaningful groups based on the integral data assessed with the INTERMED, this would support its validity and clinical use as a case mix instrument for the assessment of case complexity and health care needs.
Section snippets
Subjects
Subjects (N = 108) were recruited between November 1995 and November 1996 and were divided into two groups. Group 1 (N = 55) consisted of consecutive patients with acute, subacute, or chronic low back pain who were attending the department of Rheumatology outpatient clinic of the University Hospital of Lausanne. Group 2 (N = 53) consisted of consecutive patients with chronic low back pain applying for disability compensation at the center for disability evaluation of the University Medical
Sample
Due to major communication difficulties, five patients were excluded from the study. In addition, one patient refused participation, which lead to a definitive sample of 102 patients. Of these, there were two cases for which we did not have complete data on INTERMED, i.e., necessary to conduct hierarchical cluster analysis. Therefore, data analysis was performed on 100 patients, 49 of whom were applying for disability compensation. Table 2, Table 3 show the sociodemographic variables and
Discussion
The patients included in the study consist of two groups having similar principal complaints, i.e., benign low back pain, although having different medical and psychosocial characteristics, notably, applying for disability compensation or not. The INTERMED proves it possible to differentiate among three subgroups that differ from each other on a range of variables, seem to be homogeneous in themselves, and reflect clinically meaningful information.
The first group consists of patients with
Acknowledgements
This study has been supported by the Swiss National Foundation (Grant-No 3232-42162.95) and the European Union (grant BMH1-CT93-1180).
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