Family Practice Vol. 20, No. 6, 685-689
© Oxford University Press 2003, all rights reserved
Article |
A 5-year follow-up of general practice patients experiencing depression
Department of General Practice, University of Adelaide, South Australia 5005 and a School of Public Health and Community Medicine, University of New South Wales, Australia
Correspondence to Ian Wilson; E-mail: ian.wilson{at}adelaide.edu.au
Received 17 February 2003; Revised 19 June 2003; Accepted 14 July 2003.
Wilson I, Duszynski K and Mant A. A 5-year follow-up of general practice patients experiencing depression. Family Practice 2003; 20: 685–689.
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Abstract |
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Background. Depression is a common disease in primary care and produces significant morbidity in the community. Little is known about the outcomes of depression in general practice.
Objectives. This research set out to explore both the longitudinal management and outcomes of depression as seen in general practice.
Methods. The Medic-GP database is a collection of the medical records of >50 000 people seen in nine Australian general practices. It was used to follow the management of depressed patients over 4–5 years. Records from 1994–1995 were searched for depression or similar words. Individual records of patients whose notes mentioned depression were randomly selected and examined to determine if they were diagnosed with depression. Records of patients who were diagnosed as suffering from depression were examined to determine progress over the ensuing 5 years.
Results. Six hundred of 5889 patients were examined in detail. A total of 382 patients (63.7%) were diagnosed with depression; 219 had been diagnosed during this time interval. The main findings were 64.7% of patients were female; 93.6% of patients received an antidepressant at some time during the study; 16% of patients were referred to a psychiatrist; 7.3% were hospitalized; 30% of patients who ceased antidepressants without a recurrence had courses of antidepressants of 3 months or less; and only 22.5% of patients had a single episode of depression.
Conclusion. Unlike cross-sectional studies, this study has shown a high rate of prescription of antidepressants. GPs often prescribed short courses of antidepressants, and depression behaves as a chronic, recurrent disease.
Keywords. Antidepressive agents, chronic disease, depression, family practice, longitudinal studies.
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Introduction |
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Depression is a common, disabling disease. It is now second to hypertension as the most common chronic disease seen in general practice.1 It is estimated that by 2020 it will be the second largest burden on the Australian community.1 Overall, depression is estimated to have a prevalence of 7%, while it is present in 10% of patients seeing GPs.2 People suffering from depression have a higher morbidity and mortality than the general population.3
While it is also increasingly recognized that "primary care psychiatry is not specialist psychiatry in general practice" and the results of psychiatric research cannot be directly applied to general practice,4 the outcomes of less severe depression, as seen in general practice, have not been fully explored and "there are large gaps in the available knowledge about long-term outcomes of depression in primary care".5
Little is also known about the prescribing of antidepressants with respect to long-term outcomes for depression in general practice. A study carried out in the UK6 showed a high drop-out rate for patients prescribed antidepressants, with few patients taking the medication for more than 3 months.
Since 1996, the Data Analysis Unit at the Department of General Practice, University of Adelaide has been collaborating with GPs who use computerized record systems to document all their clinical information in a database. The database, Medic-GP, has been described in detail elsewhere.7 The collaboration has resulted in an anonymous de-identified data collection containing 55 187 patients and their 915 773 detailed clinical records from 150 GPs in nine general practices in four states of Australia.
Patients in the database have been shown7 to be representative of the patients attending all general practices in Australia in terms of age and gender in the year 1997. At the time of this study, data encompassed a 5-year time frame, from July 1994 to June 1999. All patients attending one of the Medic-GP practices are informed of the database and access to further information outlining the way in which their medical records are managed.
The Medic-GP database is ideal for examining the longitudinal history of disease. In this project, it was used to investigate the prevalence, treatments and outcomes of depression in Australian general practice. The richness of the medical records enabled us, in this study, to investigate:
- the treatments used;
- changes to the treatment regime over time;
- the co-morbidities associated with depression; and
- the outcomes of depression.
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Methods |
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The Medic-GP database was interrogated to find all medical records from the period 1 July 1994 to 30 June 1995. These records were examined to determine those that carried any annotation in that 12-month period referring to depression or similar words. The vocabulary consisted of ‘depress*’ (which enabled coverage of depression, depressed, post-partum depression), dysthymia and adjustment disorder.
Patients whose records mentioned depression were randomly selected in batches of 500 and the individual records examined. Records were excluded where the reference to depression did not indicate that the GP diagnosed that patient with depression. Reasons that a record may mention depression without arriving at a diagnosis included discussing a relative with depression, excluding depression as a diagnosis and recording that the patient felt depressed, but the practitioner feeling that the patient failed to meet the criteria for the diagnosis. Records that indicated that the patient was suffering from depression were then examined in detail and the following data extracted.
- Demographic data—date of birth and gender.
- Criteria used to make the diagnosis of depression.
- Antidepressant prescription at the time of diagnosis or at subsequent consultations.
- Changes to antidepressant prescription.
- Psychiatric and physical co-morbidities.
- Referrals to other GPs for counselling, psychiatrists, psychologists, other therapists, hospital, and referral not otherwise specified.
- Outcomes—resolution, recurrence, suicide attempt, suicide.
The distribution of treatments and changes to that treatment were analysed. Length of treatment was examined. Treatment methods were compared for persistence.
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Results |
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A total of 5889 patients who met the vocabulary criterion were identified from a search of the database. Six hundred of these patients were randomly selected and their records were inspected individually. Of the 600 patients, 382 (63.7%) were determined as having a diagnosis of depression. Subsequent analyses relate to these 382 patients. Of the 382 patients, 219 (57.3%) were newly diagnosed patients, with the remainder having been diagnosed prior to the inception of the database. Of the 219 newly diagnosed patients, only 27 (12.3%) met the diagnostic criteria set out in DSM-IV.8 Overall, 67.5% of newly diagnosed patients had three (out of five) criteria documented.
Females represented almost two-thirds (64.7%) of the sample of 382 patients. Age as at 1 January 1995 is shown in Table 1. As indicated in this table, females were most commonly 25–34 years old and males 35–44 years old.
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Of the 219 newly diagnosed patients, 205 (93.6%) had a record of an antidepressant being prescribed over the 5 years of this study. The remaining 14 patients sought counselling from their GP or were referred to other health professionals or resolved their depression without medication being prescribed.
The selective serotonin reuptake inhibitors (SSRIs) were the most frequent choice of initial antidepressant (52.2%), followed by the tricyclic antidepressants (TCAs) (38.1%). Reversible monoamine oxidase A inhibitors (RIMAs) were prescribed for almost 7.8% of newly diagnosed patients receiving antidepressants, and tetracyclic antidepressants comprised the remaining 1.9%. The most commonly initiated medications were fluoxetine (25.4% of patients), dothiepin (19.0%), sertraline (14.2%), paroxetine (12.2%) and amitryptiline (10.7%). All other medications were prescribed for <10% of patients.
Of the 107 patients commenced on an SSRI, 75.7% were maintained on that class of drug, while 12.2% were changed to a TCA and the remainder to other classes of antidepressant drug. For TCA, only 56.4% were maintained on that class of drug, while 35.9% were changed to an SSRI.
Less than 20% of the cohort had recorded co-morbid conditions (see Table 2).
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In the current study, almost 10% of patients had an anxiety disorder while 5% of patients had a reference to either alcoholism or substance abuse. Chronic medical conditions included ischaemic heart disease, cerebrovascular accident, Parkinson's disease, human immunodeficiency virus (HIV) infection and epilepsy.
There were 228 referrals (including hospitalizations) for 125 patients (32.7% of the cohort). Slightly over one-third of the referrals (36.8%) were to a GP for counselling, while 32.9% were to a psychiatrist. Of the total patient cohort, 16.0% were referred to a psychiatrist and 14.1% to a GP. Hospitalization occurred for 7.3% of the cohort. Overall, GPs alone managed 74.9% of patients.
According to the medical records, 155 patients (40.6%) had ceased antidepressants and their symptoms resolved. Sixty-nine (44.5%) of those patients had 78 recurrences of the depression. Overall, only 86 patients (22.5%) had a single episode of depression during the study period. Fourteen patients (3.7%) made 16 suicide attempts. There were no completed suicides.
A fifth of the recurrences occurred <6 months from cessation of medication, while over a quarter occurred between 6 and 12 months and another quarter between 1 and 2 years. Slightly more than 20% of recurrences occurred after 2 years.
The 108 newly diagnosed patients whose depression resolved were examined to determine the duration of antidepressant medication. Forty-nine of these patients subsequently experienced a recurrence of depression symptoms and six patients had not been managed with antidepressants by their GP at any time in the 5 years of this study. For a further 12 patients, it was unclear whether antidepressants had been stopped. For almost 30% of the remaining 41 patients, antidepressant medication was prescribed for a period of 
3 months, 50% for a period of 9 months and almost 10% of this group had been managed with antidepressants for a period of >3 years.
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Discussion |
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This study, as in any retrospective case-note audit, relies on what the GP records and, as such, has limitations. It is also based on a small number of practices that may not be typical of Australian practices. As mentioned in the Introduction, the patient age and gender distribution is typical of the wider Australian community. The other major limitation of this study is the limited use of diagnostic criteria and the resulting uncertainty of diagnostic reliability. Despite these limitations, there are a number of issues that arise from this study.
Most noticeable is the very high proportion (93.6%) of patients who are prescribed antidepressants during the 5 years of the study. This is higher than the prescribing rates seen in cross-sectional studies such as that of Mant et al.9 [45.6 antidepressants prescribed per 100 diagnoses of depression at a period (1991–1992) prior to the availability of the newer antidepressants (1995)] and the BEACH study10 (63% of patients with newly diagnosed depression). The longitudinal nature of this study and the chronic recurrent nature of depression explain this difference.
There have been no studies of the severity of depression seen in general practice, although Barrett et al.11 demonstrated an overall prevalence of 10% for depression in rural American practice, and 11.2% with significant depressive symptoms, but not meeting the criteria for a diagnosis of depression. This suggests that an unknown proportion of the depressed patients in this study may have had minor depressions.
It would appear that for the large group of GPs in this study, the diagnosis of depression is almost routinely followed by the prescription of an antidepressant at some stage in the disease.
The suggestion that GPs may be prescribing antidepressants for minor depressions is strengthened by the observation of the very short courses of antidepressants. Most guidelines12 recommend a minimum of 6 months drug treatment, with a suggestion that longer courses may reduce recurrences. In this study, 30% of patients whose depression was noted to have resolved were prescribed antidepressants for 3 months or less. Such a finding suggests that these patients did not have a major depression and that they may have responded to counselling alone or the passage of time, although absolute numbers in this group are small (41). It could be suggested that patients may be undergoing a trial of antidepressant medication, although this is not widely undertaken in Australia.
Community-based studies13 suggest that patients with depression are under-treated, particularly in relation to the prescribing of antidepressants. This study suggests that where GPs diagnose depression they prescribe medication, even if some of it is for an inadequate time. Community studies14,15 also suggest that patients prefer non-drug treatments. This study suggests that patients will take antidepressants when prescribed by a GP, at least for a short period of time.
Klinkman et al.16 described depression as being more like asthma than appendicitis. This study confirms that suggestion, with the majority (77.5%) of patients in this cohort following a chronic or relapsing course. The finding points to a need to treat depression in much the same way as is being recommended for asthma, with regular monitoring and evaluation of treatment.
Only one in five of the patient cohort had been diagnosed with a co-morbid condition. This is much lower than the rate measured in the Mental Health and Wellbeing: Profile of Adults.2 In that study, 72.2% (calculated figure) of people with an affective disorder had a co-morbid mental or physical condition. It is likely that the difference is due to the low recognition of substance abuse and anxiety when occurring with depression. These were specifically covered by the Mental Health Survey. It does not, however, explain the low rate of co-morbid chronic medical conditions in the study cohort. Other studies17 indicate a higher level of physical and psychiatric co-morbidity; however, the relative youth and lesser severity of this cohort may limit this. Most studies of co-morbidity have been carried out in severely and/or chronically depressed patients.
It is interesting to note the high rate of referrals to other GPs for counselling, although more patients (16.0%) were referred to psychiatrists. A large majority (74.9%) of patients with depression were treated by GPs alone.
The prescription of antidepressant classes is in line with experience for the 1994–1995 period. The continuation rates for SSRIs and TCAs is also in line with experience and confirm the significant swing to SSRIs that occurred at this time.
This study highlights the chronic nature of depression, the high, possibly excessive rate of prescription of antidepressants for depression in general practice and the consequent high prevalence of short courses. Perhaps the focus of depression interventions for GPs should be education and training in non-drug treatments.
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Acknowledgments |
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Funding for the project was made available by a grant to AM from ‘beyondblue’, the Australian National Depression Initiative.
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References |
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