Patients in General Practice in Denmark Referred to Physiotherapists: A Description of Patient Characteristics Based on General Health Status, Diagnoses, and Sociodemographic Characteristics.

Musculoskeletal illness is a common cause of absenteeism from work, workers' compensation claims, and disability retirement.[1-3] A population-based survey in 1994 showed that within a year, 69% of the population had experienced some sort of pain or discomfort related to the musculoskeletal system. More than half of these people considered themselves ill, and 36% had visited their own general practitioner (GP) because of their musculoskeletal symptoms.[3] The proportion of the population in Denmark reporting chronic musculoskeletal illness increased from 13% to 15.9% between 1987 and 1991,[3] and musculoskeletal illness accounts for 9.3% to 17% of all patient contacts in general practice.[4-6]

In primary health care settings, a quarter to a third of the patients have some level of psychological distress.[7,8] Most common are depression disorders and anxiety disorders, accounting for 76% of psychiatric cases in primary care.[9] Psychological distress has proven to be underrecognized in patients in general practice.[10-13] A major reason psychological distress is underrecognized is that 40% to 80% of patients with psychological distress report only their physical symptoms to their GP.[10-13] In most of these patients, the physical symptoms cannot be explained by findings of pathology (ie, "somatization"[14]). They can have symptoms from any organ system (including the musculoskeletal system), they often report multiple symptoms, and pain is a frequent complaint.[15,16]

Physical therapy interventions are commonly offered as treatment to patients with musculoskeletal illness. An increase in referrals to physiotherapists has been observed in the last few years, and the reason for this increase is unknown.[3] Forty-three percent of the patients seeing their GP about a musculoskeletal illness report subsequent referral to a physiotherapist.[17]

We believe that patients with musculoskeletal illness in general practice often have poorly defined diagnoses and that generally more patients with poorly defined diagnoses are referred to physiotherapists. We contend that patients with musculoskeletal illness can be expected to have not only worse physical health but also worse mental health than the general population. To address these hypotheses, our study had 2 aims. One aim was to describe the general health status of diagnostic subgroups of patients with musculoskeletal illness referred to physiotherapists from general practice. The other aim was to describe the general health status, diagnoses, and sociodemographic characteristics of patients with musculoskeletal illness referred to physiotherapists and compare them with patients not referred to physiotherapists and with the general population.

Methods and Materials

The results presented in this article are part of the results based on a large survey focusing on patients referred to physiotherapists from general practice in Denmark. All GPs registered with the public health insurance administration in the County of Aarhus, Denmark, by February 1996 were invited to participate in the study (N=410). They were randomly assigned to 12 periods of 8 weeks, evenly distributed during 1 year from August 1996 to August 1997. Data on age and sex distribution in the population were obtained from the public health authorities in the County of Aarhus. All GPs were requested to answer a short questionnaire whether they participated in the study or not. Data on sociodemographic characteristics and general health status were obtained from the Danish Health and Morbidity Study of 1994.[18]

One hundred ninety-four GPs participated, representing 124 (46%) different practices in the county. Participating GPs tended to have been in general practice for a shorter time, to have fewer patients listed, and to have less frequent contact with physiotherapists about the treatment of individual patients than nonparticipating GPs. Participating and nonparticipating GPs did not differ in terms of sex, type of practice (solo/group), locale (rural/city/mixed), number of GPs in the practice, and self-reported knowledge and experience in the fields of rheumatology, physical therapy, and psychiatry. The GPs' self-reported knowledge was measured by asking them whether they considered their own knowledge to be "little," "below average," "average," "above average," or "great."

Patient Inclusion

During the first 7 of the 8 weeks, the GPs recruited all patients with musculoskeletal illness being referred to physiotherapists during normal surgery hours (8 AM-4 PM). In order to be able to compare referred patients with nonreferred patients, the GPs, during the eighth week, also included patients with musculoskeletal illness who were not referred to physiotherapists. Only patients aged 18 years or over were included. Patients who would not be able to answer the questionnaires, either because of mental retardation or because of lack of knowledge of the Danish language, were excluded. Patients could be included in the study only once.

Questionnaires

Two questionnaires were used in the study: a GP questionnaire and a patient questionnaire. The GP questionnaire was filled in by the GP following a patient's visit. It contained questions about the patient's reason for visiting the GP, diagnosis, and chronicity of musculoskeletal illness. The reason for seeking treatment and the diagnosis were coded by one of the researchers (CKJ) according to the International Classification for Primary Care, Danish Version (ICPC).[19] Diagnoses were categorized as "well defined" or "poorly defined" a priori, based on consensus between 2 authors (CKJ and FO). The Appendix lists the ICPC codes and diagnoses and the number of patients with these diagnoses, grouped according to those who were referred to physiotherapists and those who were not referred to physiotherapists. The diagnoses are supposed to reflect the GP's opinion about the patient's condition and do not necessarily fulfill specific criteria. Often the diagnoses are merely a symptom, reflecting the reality of daily clinical practice in primary care, where many patients do not fulfill criteria for a specific diagnosis based on verifiable pathology.[20] The questionnaire also contained a set of questions about psychological distress and somatization. The results of these questions are reported elsewhere.[21,22]

The patient questionnaire, which the patient returned directly to the research unit by mail in a postage-prepaid envelope, contained sociodemographic information and the Danish version of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36).[23] The SF-36 includes 35 items related to 8 concepts of health: physical functioning (PF), role limitations due to physical problems (RP), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF), role limitations due to emotional problems (RE), and mental health (MH). For each health concept, scores are coded, summed, and transformed to a scale with scores ranging from 0 to 100, with higher scores indicating better health. In addition, the physical component scale (PCS) and mental component scale (MCS) scores were calculated.[24] They give an overall measure of physical health and mental health, respectively. A PCS or MCS score of 50 indicates the norm for the general population in the United States. Higher scores indicate better health. Validation studies from different countries, including Denmark, have consistently shown that SF-36 provides reliable and valid measurements of general health in different populations.[25-29]

Statistical Analyses

Proportions are reported as percentages with 95% confidence intervals. Statistical testing of differences in proportions was done by chi-square analysis, with a test for trends. Between-group differences in scores on rating scales were analyzed by the Mann-Whitney U test because the scores were not normally distributed. Differences in mean scores between the study population and the reference population were analyzed by a t test because we believe the t test for large samples is robust with regard to departure from normality. Groups to be compared were defined a priori. Consequently, we believe that correction for multiple significance testing was not necessary. To investigate whether differences between subgroups of patients were due to confounding by age and sex, we conducted a series of logistic regression analyses. Dependent variables were the individual SF-36 health concepts dichotomized into the lowest and highest scoring halves of the study population. Independent variables were age, sex, and diagnostic group. A significance level of .05 was used.

Results

During the 1-year period of the study, the GPs included 2,042 patients fulfilling the inclusion criteria. Forty-four patient questionnaires were excluded from the analysis because no corresponding GP questionnaire was returned. Of the remaining patients, 1,720 were referred to a physiotherapist and 278 were not referred to a physiotherapist. The response rate was 63% for the referred patients and 49% for the nonreferred patients. There was no difference in diagnoses or in the rating by the GP of illness chronicity and psychological distress between the respondents and the nonrespondents (data not shown). However, more women than men responded (66% versus 55%), and the median age of respondents was 46 years compared with the nonrespondents' median age of 44 years.

General Health Status in Diagnostic Subgroups of Patients Referred to Physiotherapists

The group with poorly defined diagnoses had lower scores in the mental health concepts (MH, RE, VT) and social functioning (SF) than the group with well-defined diagnoses (Fig. 1). The mean MCS score was 53.4 among patients with a well-defined diagnosis and 49.5 among patients with a poorly defined diagnosis (Mann-Whitney U test, P [is less than] .00001). However, they did not differ in the physical concepts (PF [P=.62], RP [P=.79], BP [P=.33], and PCS [P=.45]). The differences between diagnostic groups remained when controlling for age and sex in a logistic regression analysis (Tab. 1).

[Figure 1 ILLUSTRATION OMITTED]

Table 1. Logistic Regression Analysis(a)

SF-36        Crude       Adjusted    95% Confidence
Subscole   Odds Ratio   Odds Ratio      Interval

PF            0.9          0.9          0.7-1.2
RP            1.0          1.0          0.8-1.3
BP            0.9          0.9          0.7-1.2
GH            0.8          0.8          0.6-1.0
VT            0.6          0.7          0.5-0.9
SF            0.6          0.6          0.5-0.8
RE            0.7          0.7          0.5-0.9
MH            0.7          0.7          0.6-0.9

(a) Odds ratios for belonging to the highest scoring half within the individual subscale of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) given a poorly defined diagnosis. Adjusted odds ratio after correcting for age and sex.

General Health Status

The general health profile of referred and nonreferred patients is shown in Figure 2. Both groups scored lower (t test, P [is less than] .00039) on all health concepts and especially on the physical health concepts (PF, RP, BP) compared with a reference group from the general Danish population.[18] Referred patients had slightly lower scores than nonreferred patients on all health concepts, but the differences were not statistically significant (Mann-Whitney U test, P=.061-.329).

[Figure 2 ILLUSTRATION OMITTED]

Diagnoses

The 2 most frequent diagnoses among the referred patients were "myopain" and "back-related diagnoses," accounting for 37.6% and 18.1% of all primary diagnoses. Myopain was less common among nonreferred patients than among the referred patients. The nonreferred patients had more poorly defined back problems and fewer well-defined back problems compared with the referred patients. Overall, the GPs were not able to establish a well-defined diagnosis in a greater number of referred patients compared with nonreferred patients (70% versus 57%) (Tab. 2).

Table 2. Frequencies of Different Diagnoses Among Patients With Musculoskeletal Illness in General Practice in Denmark (95% Confidence Interval in Parenthesis)

                                                      ICPC(b)
Diagnosis Group(a)    Referred        Not Referred    Code

Myopain (excluding    37.6%           22.8%           L19.5
current injury)       (35.3%-39.9%)   (17.9%-27.8%)

Poorly defined        10.0%           17.0%           L02, L79.2,
back-related          (8.6%-11.5%)    (12.6%-21.5%)   L84
diagnoses

Well-defined          3.8%            3.6%            L86
back-related          (2.9%-4.7%)     (1.4%-5.8%)
diagnoses

Synovitis/            8.0%            10.5%           L93, L99.1,
inflammation          (6.7%-9.3%)     (6.9%-14.1%)    L99.3,
of bursae                                             L99.8

Injuries              6.6%            9.4%            L72-L78,
                      (5.4%-7.8%)     (6.0%-12.9%)    L79.0,
                                                      L79.2

Other poorly          5.3%            3.6%            L01, L83.0,
defined               (4.3%-6.4%)     (1.4%-5.8)      L83.1,
neck-related                                          L83.4,
diagnoses                                             L83.5

Poorly defined        4.3%            5.8%            L03, L79.4
low back-related      (3.3%-5.2%)     (3.0%-8.6%)
diagnoses

Whiplash              3.8%            2.2%            L83.5
                      (2.9%-4.7%)     (0.5%-3.9%)

Other (including      20.7%           25.0%           Remaining
nonmusculoskeletal    (18.7%-22.5%)   (19.9%-30.1%)   codes (see
diagnoses)                                            Appendix)

N(c)                  1,712           276

Diagnosis group(a)    Referred        Not Referred    ICPC Code

Poorly defined        70%             57%             See
(including            (68%-72%)       (51%-63%)       Appendix
nonspecified
headache and
tension headache)

Well-defined          30%             43%             See
                      (28%-32%)       (37%-49%)       Appendix

N                     1,644           270

Excluded              68              6               See
(nonmusculoskeletal                                   Appendix
diagnoses)

Total(c)              1,712           276

(a) See the key to the grouping procedure in the Appendix.

(b) ICPC = International Classification for Primary Care, Danish Version.[19]

(c) There was no information about diagnosis for 8 referred patients and 2 nonreferred patients.

Sex, Age, and Sociodemographic Characteristics

There were relatively more women among referred patients than among nonreferred patients and in the general population (Tab. 3). The age distribution of the patients did not differ between groups. There were fewer patients aged 18 to 24 years and more patients aged 45 to 54 years compared with the general population of the county (Tab. 3).

Table 3. Sex and Age Distribution Among Patients With Musculoskeletal Illness in General Practice in Denmark: Patients Referred and Not Referred to Physiotherapists Compared With a Representative Sample (95% Confidence Interval in Parenthesis)

                                             General
                                           Population
                          Not             in the County
Sex       Referred        Referred        of Aarhus(a)

Women     63.3%           53.6%               51.0%
          (61.0%-65.6%)   (47.7%-59.5%)

Men       32.4%           43.9%               49.0%
          (30.2%-34.7%)   (38.1%-49.7%)

Missing    4.2%            2.5%
          (3.3%-5.2%)     (0.68%-4.4%)

N         1,720           278                493,640

                                             General
Age                                        Population
Group                     Not             in the County
(y)       Referred        Referred        of Aarhus(a)

18-24      8.1%           10.4%               16.0%
          (6.9%-9.4%)     (6.8%-14.0%)

25-34     21.5%           21.9%               20.4%
          (19.6%-23.5%)   (17.1%-26.8%)

35-44     18.1%           19.4%               18.4%
          (16.3%-19.9%)   (14.8%-24.1%)

45-54     23.4%           20.1%               17.9%
          (21.4%-25.4%)   (15.4%-24.9%)

55-64     14.5%           12.2%               11.3%
          (12.9%-16.2%)   (8.4%-16.1%)

65-74      8.8%            8.6%                8.9%
          (7.5%-10.2%)    (5.3%-11.9%)

75+        5.5%            7.2%                7.1%
          (4.4%-6.6%)     (4.2%-10.2%)

N         1,720           278                493,640

(a) Data from the public health authorities in the County of Aarhus.

Employment status and marital status (Tab. 4) were very similar for referred and nonreferred patients, but there were a few more salaried employees and people receiving disability pensions and slightly fewer students/apprentices and people receiving old age pensions among referred patients compared with the sample representative of the general Danish population. A few more people in the study population were married as opposed to single compared with the general Danish population.

Table 4. Sociodemographic Characteristics of Patients With Musculoskeletal Illness in General Practice in Denmark: Patients Referred and Not Referred to Physiotherapists Compared With a General Population Sample (95% Confidence Interval in Parenthesis)

                                                    Danish Health
                                                    and Morbidity
                                                    Survey of
Employment Status   Referred        Not Referred    1994(a)

Self-employed        5.3%            5.3%            7.3%
                    (3.9%-6.6%)     (1.5%-9.1%)     (6.6%-8.1%)

Salaried employee   39.2%           33.8%           34.2%
(white collar)      (36.3%-42.2%)   (25.8%-41.9%)   (32.8%-35.6%)

Worker (skilled     13.2%           18.8%           14.1%
and unskilled)      (11.2%-15.2%)   (12.2%-25.4%)   (13.1%-15.1%)

Old age             13.2%           18.0%           17.6%
retirement          (11.2%-15.2%)   (11.5%-24.6%)   (16.5%-18.7%)

Disability           8.4%            5.3%            5.9%
retirement          (6.8%-10.1%)    (1.5%-9.1%)     (5.2%-6.6%)

Unemployed/social    6.2%            5.3%            7.6%
welfare             (4.8%-7.6%)     (1.5%-9.1%)     (6.8%-8.4%)

Student/             6.4%           10.5%           11.3%
apprentice          (4.9%-7.8%)     (5.3%-15.7%)    (10.4%-12.2%)

Other                8.1%            3.0%            2.0%
                    (6.5%-9.8%)     (0.1%-5.9%)     (1.6%-2.4%)

N                   1,083           133             4,668

People not            628           143             1,332
participating

People not              9             2                 0
answering
question
                                                    Danish Health
                                                    and Morbidity
                                                    Survey of
Marital Status      Referred        Not Referred    1994(a)

Married or          71.8%           70.4%           66.9%
cohabitant          (69.1%-74.5%)   (62.7%-78.1%)   (65.5%-68.3%)

Single, never       13.0%           15.6%           19.9%
married             (11.0%-15.0%)   (9.4%-21.7%)    (18.8%-21.0%)

Single,              8.5%            4.4%            5.6%
divorced            (6.8%-10.2%)    (1.0%-7.9%)     (4.9%-6.3%)

Widow/widower        6.7%            9.6%            7.4%
                    (5.2%-8.1%)     (4.7%-14.6%)    (6.6%-8.2%)

N                   1,083           133             4,659

People not            628           143             1,332
participating

People not             10             0                 0
answering
question

(a) From the Danish Health and Morbidity Study of 1994, conducted by the Danish Institute for Clinical Epidemiology (68.3% of a population sample of 6,000 people representative of people 16 years of age or older).[18]

Discussion

Patients with musculoskeletal illness in general practice differed very little from the general population in terms of age, sex, and sociodemographic characteristics. There were relatively more women among the referred patients than among the nonreferred patients. This finding is consistent with information from the public health insurance registers in the County of Aarhus showing that the women-men ratio among patients referred to physiotherapists is 2:1 (Jorgensen and Olesen, unpublished observations). Whether this was a result of a higher need or higher demand for physical therapy interventions by women (and their GPs) is not known.

Musculoskeletal illness is common in patients in general practice, but the GPs were able to make only poorly defined diagnoses (eg, myopain) for most of the patients in our study. Nevertheless, the physical health and mental health of the group as a whole, as measured by the SF-36, was affected compared with the general population. This was also reported by Mossberg and McFarland[30] for patients with musculoskeletal illness in outpatient physical therapy clinics in the United States. However, the patients in that study had lower scores on the physical concepts compared with our study group. Mossberg and McFarland's study group was very similar to ours in terms of age distribution (mean age=43.2 years, SE=1.4), sex (72% women), and clinical conditions, and the difference in physical health can well represent a true difference in the severity of musculoskeletal illness among patients referred to physiotherapists in Denmark and in the United States. Reasons for this could be differences in the GPs' indications for referral or differences in patients' demands for physical therapy interventions. It is known that there is a wide variation in referral rates from individual GP practices, but little is known about factors determining this variation and GPs' inclination to refer patients (Jorgensen and Olesen, unpublished observations).

We believe the scientific rationale for using highly specialized health care workers such as physiotherapists to treat patients with poorly defined conditions (eg, myopain) should be questioned, especially when the efficacy of the treatment is not well documented.[31] Nevertheless, this group of patients was the most common among the referred patients. The finding that these patients scored lower on the mental health concepts of SF-36 supports our primary hypothesis and suggests that physiotherapists are not chosen solely to provide specific treatments of well-defined physical diagnoses, but apparently also in the case of less well-defined diagnoses in patients with low scores on mental health concepts. If this is part of a biopsychosocial approach to treatment and if psychosocial issues are also dealt with in a relevant way, it may well represent a rational treatment strategy. If not, it suggests that psychological distress presented as musculoskeletal symptoms is to some extent misdiagnosed by the GPs as a physical condition and treated with physical therapy. Even if physiotherapists are aware of psychosocial problems among patients referred to them and take that into account when treating their patients, we believe it is important that the GPs also identify and deal with the psychosocial problems.

Generalizing the results of this study to other populations should be done with caution, bearing in mind that the overall response rate of the patients was 61% and that a little less than half of the GPs in the county participated. However, the patients who responded to our survey did not differ markedly from the nonrespondents, apart from the fact that more women than men responded. The over-representation of women tends toward underestimating the score in all health concepts. This tendency was controlled for in the statistical comparisons. There were few differences between the participating and nonparticipating GPs. It is unlikely that the participating GPs were more interested in and knowledgeable about musculoskeletal illness than the nonparticipating GPs, thereby attracting certain types of patients with musculoskeletal illness.

Conclusion

Patients with musculoskeletal illness in general practice often receive poorly defined diagnoses (eg, myopain). Of the patients referred to physiotherapists, the subgroup of patients with poorly defined diagnoses had lower scores on mental health concepts than the subgroup of patients with well-defined diagnoses, which suggests that a biopsychosocial approach is especially important in this group of patients as opposed to an entirely biomedical approach. The fact that there were more patients with poorly defined diagnoses among those patients referred to physiotherapists suggests to us that physical therapy interventions are not always used for specific indications. If we want to understand the increasing prevalence of musculoskeletal illness and the demand for physical therapy interventions, we believe that analysis of both physical and psychosocial aspects of musculoskeletal illness is needed.

References

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[2] Badley EM, Rasooly I, Webster GK. Relative importance of musculoskeletal disorders as a cause of chronic health problems, disability, and health care utilization: findings from the 1990 Ontario Health Survey. J Rheumatol. 1994;21:505-514.

[3] Brinck B, Rasmussen NK, Kjoller M, Thomsen LK. Musculoskeletal Illness in Denmark: Prevalence and Illness Behavior. Copenhagen, Denmark: Danish Institute of Clinical Epidemiology; 1995.

[4] Ovesen L, Juul S, Mabeck CE. Contacts to General Practice: Aarhus County 1993. Aarhus, Denmark: Public Health Insurance, Aarhus County; 1997.

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[15] Fink P. Persistent Somatization [dissertation]. Aarhus, Denmark: University of Aarhus; 1997.

[16] Katon W. Panic disorder and somatization: review of 55 cases. Am J Med. 1984;77:101-106.

[17] Lyster G, Michelsen L. Report of Danish Physiotherapists, Client Identification, September 1994. Copenhagen, Denmark: AIM-Nielsen; 1994. Job no. D8833. 94.

[18] Danish Institute for Clinical Epidemiology. Danish Health and Morbidity Survey 1994. Available at: http://www.dike.dk/html/udgivel/ engsusy/engsusy.htm. Accessed 1998.

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[21] Jorgensen CK, Fink P, Olesen F. Psychological distress among patients with musculoskeletal illness in general practice. Psychosomatics. 2000;41 (4):321-329.

[22] Jorgensen CK, Fink P, Olesen F. Psychological distress and somatisation as prognostic factors in patients with musculoskeletal illness in general practice. Br J Gen Pract. 2000;50:537-541.

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Appendix.

Diagnosis and Number of Included Patients With Muscoloskeletal Illness in General Practice in Denmark, Coded According to the International Classification for Primary Care, Danish Version[19] (ICPC) and Grouped Into Patients Who Were Referred to Physiotherapists and Patients Who Were Not Referred to Physiotherapists

[TABULAR DATA NOT REPRODUCIBLE IN ASCII]

CK Jorgensen, MD, PhD, is Medical Doctor and Research Fellow, Research Unit and Department of General Practice, University of Aarhus, Vennelyst Blvd 6, 8000 Aarhus C, Denmark ([e-mail]). Address all correspondence to Dr Jorgensen.

P Fink, DrMedSci, PhD, is Psychiatrist and Consultant, The Research Unit for Functional Disorders, Psychosomatics, and Consultation-Liaison Psychiatry, Aarhus University Hospital, Aarhus, Denmark.

F Olesen, DrMedSci, is Professor, Research Unit for General Practice, University of Aarhus.

All authors provided concept/research design, writing, and data analysis. Dr Jorgensen and Dr Olesen provided subjects, data collection, project management, and fund procurement. Dr Olesen provided facilities/equipment and administrative support. Dr Fink and Dr Olesen provided consultation (including review of manuscript before submission). The authors thank the general practitioners in the County of Aarhus, participating patients, and physiotherapists for their invaluable contribution to the data collection.

The project was approved by the Scientific Ethics Committee in the County of Aarhus and the Danish Data Protection Agency, and it was performed according to the Helsinki Declaration.

The study was funded by the Aarhus County Health Services Research Initiative, the Ministry of Health's National Health Fund for Research and Development (grant no. 1400/9-99-1996), the Danish Society of General Practitioners' Lundbeck Grant, the General Practitioners' Foundation for Education and Development, the Danish Rheumatism Association (grant no. 233-955-31.1.96 MP), and the Danish Medical Association Research Fund.

This article was submitted June 8, 1999, and was accepted August 9, 2000.