Does cash payment influence a GP’s decision to prescribe antibiotics?

Introduction

Antimicrobial resistance is a major public health concern and one of the primary factors contributing to resistance is the unnecessary use of antimicrobials. Many countries have developed strategies in order to promote the rational use of antibiotics. Ireland is only one of three European countries where outpatient antibiotic use is increasing, at a rate of 3% per year since 2000.

The majority of antibiotic prescribing is conducted by General Practitioners (GPs) in the community, and wide variation is known to exist. The volume of antibiotics prescribed that are unnecessary in the community is unknown but it is believed that a number are used to treat minor respiratory tract infections. These conditions such as the common cold, sore throat, acute otitis media and acute bronchitis have no compelling evidence to support the use of antibiotics in their treatment. There are many external (non-clinical) factors that influence a GP’s decision to prescribe, e.g., patient pressure and social factors. Patient pressure and time restraints have been quoted as potential reasons that GPs provide treatment, despite clinical evidence suggesting it is not necessary.

There is considerable debate internationally about how primary care services should be funded and delivered. As a result, policy-makers have used a wide variety of strategies to make the best use of the national resources and this often becomes a political debate. Access to primary care services operates on a two-tier system in the Republic of Ireland (ROI). General Medical Service (GMS) card holders attend GP surgeries free of charge and are entitled to free medications. Eligibility is means tested and in 2009, 33% of the population in Ireland were GMS card holders. When characteristics such as level of health are controlled, having a GMS card remains a very strong predictor of GP utilisation.

Non-card holders (private patients) must pay a non-subsidised fee to visit their GP. Almost all GPs in Ireland (96%) operate a mixture of GMS and private practice. In other countries such as the UK, GPs working for the National Health Service (NHS) are not allowed to charge patients for their family health services. There are many reasons that this regulation was introduced. A GP working in an unregulated private market may have an incentive to provide above the required services, an event known as ‘supplier-induced demand.’ GPs can also be under more pressure from patients to provide unnecessary treatments due the pressure of the payment involved. The method of GP remuneration and patient demands have been acknowledged as some of the main factors that influence the practice of GPs. In Canada, both salary-based and fee-for-service GPs exist and it was found that there was an association between fee-for service GPs and high rates of antibiotic use. We postulate that this payment may affect the GP’s decision to prescribe antibiotics in consultations in ROI.

Aim

The aim of this study was to ascertain whether there was a variation in practice in prescribing antibiotic between GMS and private patients in the ROI.

Method

Ethical approval was granted by the local ethics committee. All GPs nationally attending continuing medical education (CME) groups were invited to participate from October 2008 to April 2010. Ireland has a CME attendance of over 1,000 GPs. Participating GPs gathered data on 100 consecutive consultations including diagnosis and patient characteristics. When an antibiotic was prescribed during the consultation, details of the prescription and directions for use were recorded, for example, where a delayed or ‘deferred’ antibiotic prescription was given to dispense at a later time if necessary, as agreed by GP and patient.

Analysis

Data was analysed using Microsoft Office Excel® (2007) and Statistical Package for the Social Sciences (SPSS®, Chicago, Illinois) version 15.0. The Pearson’s chi-squared tests (χ2) were performed to assess if associations existed between categorical variables; if the p-value <.05 then there was a statistical relationship between the two variables. Odds ratios (ORs) were calculated to measure the strength of these associations; an OR of 1 implies that the occurrence is equally likely in both groups. An OR >1 implies that the occurrence is more likely in one group; an OR <1 implies that it is less likely. The Mann-Whitney test was used to compare numerical variables, i.e., to test whether one variable tends to have values higher than the other (a p-value here <0.05 signifies a statistical difference) and 95% confidence intervals (CI) were calculated.

Results

Data were collected from 170 GPs, which resulted in 16,800 consultations. These GPs were from all over the ROI and a range of demographics and settings (e.g. urban/rural) were represented. The mean (±SD) number of consultations recorded per GP was 98.82 ±5.85. This took an average of 3-5 working days for the GP to complete.

The mean age of GMS patients was 49.65 ± 26.13 years, while the mean age of private patients was 33.82 ± 20.59 years (p<0.0005, 95% CI:13.37-17.49). Antibiotics were prescribed at 3,380 (20.12%) consultations. Half of the antibiotics prescribed were for GMS card holders (1,656; 48.99%), 44.85% (1,516) were for private patients and 6.15% (208) were of unknown type due to missing data. The rate of antibiotic prescriptions in both groups was similar (GMS: 18.33%, Private: 21.59%). However, private patients were more likely to receive an antibiotic prescription (p<0.005, OR 1.22). People aged ≥ 65 years were less likely to receive an antibiotic (p <0.001, OR 0.69).

Private patients were also more likely to receive a deferred prescription (p=0.006, OR 1.34) (Table 1). The majority of antibiotics prescribed for both groups were for diagnosis or symptoms of a respiratory-related illness. A higher percentage of private patients (1,037, 68.40%) compared to GMS patients (1,028, 62.08%) received an antibiotic for a respiratory related illness. Private patients were more likely to receive an antibiotic when consulting with a respiratory illness (p<0.0005, OR 1.47) (Table 1).

Discussion

GMS patients are known to be higher consumers of medical care; GMS card holders had an average of 6 visits per year in 2001, compared with 2.3 visits for those without a medical card. This can be partly explained by the higher age and worse physical and mental health of the GMS population; and partly explained by the reluctance of private patients to pay the fee. Research to date on antibiotic prescribing in Ireland has not included non GMS card holders. Pharmacy sales data is available but holds no individual level information. Unlike other countries, information on diagnostic indications that are being treated with antibiotics in the community is not known in Ireland, although this data is vital in developing strategies to reduce antibiotic use.

This study has shown that private patients are slightly more likely to receive an antibiotic prescription (1.22 times). GPs often quote expectation and pressure from patients as a reason for antibiotic prescribing and this pressure would be expected to be increased when there is payment involved.

Older patients are more likely to develop complications such as pneumonia following a respiratory infection and therefore antibiotic use in this cohort would be expected to be higher than the general population. This study found that older patients were less likely to receive an antibiotic, indicating that inappropriate prescribing is occurring more in the younger, healthier population.

A limitation of the study was that GPs did not record the duration of symptoms of each patient. This may influence the decision of the GP to prescribe antibiotics. It is generally thought that on average private patients wait longer to visit their GP due to the cost implications and therefore likely to have worsening symptoms. This will be studied further in qualitative work that is currently being conducted.

Conclusion

These results demonstrate that whether the patient pays for the GP consultation can have an influence on the GP’s decision to provide an antibiotic prescription. Private patients are more likely to receive an antibiotic prescription. This was not expected, as GMS patients are higher users of medical care due to the higher age bracket and the lower socio-economic background of the group, and further supports the theory that external factors have a role in antibiotic prescribing in primary care. Deferred prescriptions were more likely to be prescribed to private patients, negating the need to re-consult if symptoms deteriorated. Age was also shown not to be a contributing factor, which was also not expected as antibiotics have shown to have more protective benefits in the older population. More research is required to follow-up both GMS and private patients to assess clinical outcomes post-GP consultation.

I would like to thank my supervisors Prof. Colin Bradley and Dr. Stephen Byrne. I would also like to thank the GPs who participated in the study, in particular the CME tutors for their support.
Funded by the Health Service Executive (Strategy for the Control of Antimicrobial Resistance in Ireland)