The Utilization of Medical Services by Doctors in Outpatient Practice

A Case–Control Study Based On Billing Data From the Thuringian Association of Statutory Health Insurance Physicians

Physicians are in a different position and have specific barriers in their own health care utilization compared to the non-physician population. In addition to their medical knowledge and deeper understanding of how the health care system works, they can self-prescribe diagnostic testing as well as treatments. The fact that physicians often treat themselves and use informal consultations is well known (1−3). Among the specific barriers to accepting medical help are concerns about confidentiality, professional consequences, fear of stigmatization, time constraints, and a medical culture that implies that physicians should not be sick (2, 3). It can therefore be assumed that the utilization behavior of physicians is different. An analysis of secondary data showed that Taiwanese physicians had a lower use of the outpatient sector compared to the general population (4). Furthermore, empirical studies on the topic are scarce internationally and non-existent in Germany. The aim of our study was to fill this gap.

Methods

We analyzed billing data of the Thuringian Association of Statutory Health Insurance Physicians (Kassenärztliche Vereinigung Thüringen, KVT). We compared the utilization of Statutory Health Insurance (SHI)-insured outpatient services providing contract physicians and psychotherapists of the KVT Physicians with a control group of non-physician patients residing in the KVT area and having at least one outpatient physician utilization in 2019. For age/sex based matching, a subgroup was created from the total of all non-physician SHI patients and a random sample was drawn from it at a ratio of 1:10. We compared overall outpatient service utilization (cases of general practitioner and specialist treatment), utilization of selected outpatient services, and differences in morbidity characteristics: number of long-term diagnoses (based on ICD-10 three-digit codes), most frequent long-term diagnoses, number of disease management program (DMP)-relevant diagnoses.

Results

We included 1498 physician patients (33.6% of the Thuringian population of physicians, psychotherapists in outpatient practice), of whom 274 (= 18.3%) were psychological psychotherapists, as well as 14 980 control patients. Physician patients were less likely to have a DMP-relevant diagnosis (odds ratio [OR] = 0.586, p<0.001) and fewer long-term diagnoses (incidence rate ratio [IRR] = 0.595, p<0.001) compared to control patients.

General utilization of outpatient medical services

On average, physician patients accounted for fewer treatment cases than control patients. IRR was 0.871 (p<0.001), i.e. the number of cases was lower by (1−IRR) × 100 = 12.9%. Physician patients were less likely to seek general practitioner care, both in terms of the proportion of patients with at least one utilization of general practitioner services (OR = 0.265; p<0.001) and in terms of the number of cases of general practitioner care per patient (IRR = 0.741; p<0.001) (Table). Hence, the odds of using general practitioner services at least once were lower by (1-OR) × 100 = 73.5% among physician patients. Younger physician patients used GP care at a similar rate as control patients of the same age. GP treatment was (significantly) less frequently observed among middle-aged and older physician patients compared to control patients. Age moderated both the group difference in utilization rate (OR = 0.951; p<0.001) and in the number of GP treatment cases (IRR = 0.995; p = 0.001). Specialists tended to be consulted more frequently (OR = 1.197; p = 0.054) by physician patients.

Table

Patient characteristics and service utilization of physician patients and control patients

Utilization of selected outpatient services

A lower proportion of physician patients used at least one general preventive service (cancer screening and health check) compared to control patients (OR = 0.812, p<0.001). DMP service were less frequently utilized (OR = 0.244, p<0.001), even if we only considered patients with DMP-relevant diagnoses. Physician patients utilized vaccination services more frequently (OR = 2.002, p<0.001) and the on-call services of SHI-accredited physicians less frequently (OR = 0.705, p<0.001). There were no differences in the utilization of medical imaging services.

Discussion

The overall lower utilization of outpatient services by physician patients is consistent with the findings of the study by Chiu (4). The previously unreported age-related lower utilization of general practitioners by physician patients deserves special mention. Possible reasons include: increase in knowledge with professional experience, greater sense of control, as well as particular occupational demands in midlife, including associated barriers (for example, lack of time). Future studies should analyze the extent to which activity-related characteristics (e.g., self-employment) have an influence.

A know-how-related lower perceived need as well as the possibility of self-treatment could play a role in the comparatively lower utilization of general preventive services, disease management programs and on-call services of SHI-accredited physicians. Doubts about the medical benefits of DMP programs (5) are another possibility. Other aspects could be time requirements due to regular appointments as well as an aversion to dependency or loss of autonomy. However, the exact reasons for the divergent utilization of general preventive services (lower) and vaccination services (higher) have yet to be clarified.

We cannot report data for 66.4% of KVT physicians and psychotherapists in outpatient practice because they had private health insurance or there was no utilization of medical services in 2019. The younger study population with a higher proportion of women and more physicians working part-time compared to the population of Thuringian physicians results from the fact that SHI-insured physicians were selected. As a result, differences to the general population may tend to be underestimated. A further limitation is that it is not possible to match the educational level of the control patients. Whether the diagnosis-based lower morbidity of physician patients is due to lower utilization of medical services or better health status remains an open question.

Bearing this in mind, it was for the first time possible to prove a different utilization of the health care system by physicians compared to non-physician patients in Germany. This supports the notion of physicians as a population with specific conditions and specific behaviors regarding their own health and illness. Further studies that include physicians with private health insurance, hospital physicians, and inpatient services should be conducted.

Sven Schulz, Franziska Meissner, Florian Wolf, Antje Freytag

Institute of General Practice and Family Medicine, Jena University Hospital, Friedrich-Schiller University, Jena, Germany (Schulz, Meissner, Wolf, Freytag),

Funding

The research project is funded by the Central Research Institute for Ambulatory Health Care in Germany (Zentralinstitut für die kassenärztliche Versorgung in der Bundesrepublik Deutschland, Zi) as part of the 2016 program to promote health services research.

Conflict of interest statement

The authors declare no conflict of interest.

Manuscript received on 23 November 2022; revised version accepted on 21 February 2023

Translated from the original German by Ralf Thoene, MD.

Cite this as:
Schulz S, Meissner F, Wolf F, Freytag A: The utilization of medical services by doctors in outpatient practice—a case–control study based on billing data from the Thuringian Association of Statutory Health Insurance Physicians. Dtsch Arztebl Int 2023; 120: 505–6. DOI: 10.3238/arztebl.m2023.0053

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