Blood glucose testing for adults prescribed atypical antipsychotics in primary and secondary care

AIMS AND METHOD

The routine monitoring of blood glucose indices for all patientson atypical antipsychotics in 2004 in a rural adult psychiatricsector was examined. Pragmatic and practical standards werebased on consensus expert opinion, National Institute for ClinicalExcellence and prescribing guidelines.

RESULTS

The audit was completed on 60 atypical antipsychotic prescriptions.Testing of blood glucose prior to the initiation or changeof an atypical antipsychotic was largely followed, with anoverall adherence rate of 82%. However, there were large differencesin testing between in-patient and community settings. Routineyearly monitoring in the community was inadequate, with anadherence rate of 63%.

CLINICAL IMPLICATIONS

There is a welcome emphasis on the physical health of thosewith severe and enduring mental illness. New initiatives, includingprescribing guidelines, the care programme approach and primarycare registers, offer the opportunity to develop consistencyand coordination between primary and secondary care in theroutine monitoring of psychiatric treatments and physical healthin these patients.

Introduction

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Introduction

It has been estimated that the prevalence of type 2 diabetesin people with schizophrenia is around 2-4 times higher thanin the general population (Bushe & Holt, 2004). The complicationsof type 2 diabetes can lead to significant physical morbidity but these may be limited by effective monitoring and good earlymanagement of the disease (National Institute for Clinical Excellence, 2002a).

Evidence suggests that treatment with antipsychotic medicationincreases the risk of developing diabetes. Although most studiesare retrospective they generally report a higher rate of diabetesin those on atypical preparations compared with typical antipsychotics (Haddad, 2004). It remains uncertain whether any particularatypical preparation is more likely to cause type 2 diabetesthan another and it is therefore prudent to consider the changesin glucose metabolism as a class effect for these drugs (Koro et al, 2002; Newcomer et al, 2002; Howes et al, 2004).

Since a diagnosis of schizophrenia and its treatment with anantipsychotic both increase the risk of impaired glucose toleranceand diabetes, patients should expect routine, standardisedmonitoring and screening (Haupt & Newcomer, 2001; Boilson & Hamilton, 2003; Expert Group, 2004). In-patient surveys of blood glucose monitoringand testing for diabetes in those on antipsychotics indicatethat this is neither routine nor systematic and little is knownabout the screening practices in primary care/community populations prescribed these medications (Boilson & Hamilton, 2003;Taylor et al, 2004).

Method

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Method

The sample comprised all adult patients in a sector of ruralDerbyshire who were prescribed atypical antipsychotics in 2004.Standards were developed based on the proposed pragmatic pathwayfor managing diabetes risks in those prescribed atypical antipsychoticsfrom the consensus summary of the Expert Group (2004), theMaudsley Prescribing Guidelines (Taylor et al, 2003), theNational Institute for Clinical Excellence (NICE) guidelines(NICE, 2002b), clinicians' best practice and local service expectations. The standards are shown in Table 1.

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Table 1. Adherence to audit standards

Patients were identified using psychiatric case notes, trustpharmacy records and general practitioner (GP) prescribingrecords. Information was gathered from multiple sources, includingpathology and pharmacy records and psychiatric and GP casenotes. Blood monitoring took place at Derby City Hospital.All information was recorded using an audit sheet designed to investigate the standards. A pilot study of five patients wasinitially undertaken. Diagnoses were recorded according toICD-10 (World Health Organization, 1993) from the trust registerand using information in medical notes. Basic descriptive statisticshave been used to collate results.

Results

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Results

Population, diagnosis and prescriptions
The sector covers a total population of approximately 40 000.There were a total of 55 patients on atypical antipsychoticmedications (30 men and 25 women); 41 had a primary diagnosisof functional psychosis (ICD-10 codes F20-29), 12 an affectivepsychosis (F30-39) and 2 other diagnoses of organic mania (F06.3)and emotionally unstable personality (F60.3) respectively. The audit was completed on the total number of atypical prescriptionscripts (60) over the year January to December 2004. This accountedfor some patients who within the year had both started andchanged atypical antipsychotic medication.

There were 10 patients who had a definitive diagnosis of type2 diabetes. Their average age at the time of audit was 53 yearsand their median duration of treatment 40 months. There were7 that had been diagnosed with diabetes after prescriptionof an atypical antipsychotic; 3 had been diagnosed within theyear of the audit by their GP following a routine random bloodglucose and subsequent glucose tolerance test.

Table 2 gives details of the drugs prescribed, the mean ageof the patients and the median duration of treatment for eachmedication.

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Table 2. Atypical antipsychotics according to number of prescriptions, patient age and duration of treatment

Standards
Adherence to each of the standards is shown in Table 1. Theoverall number of instances of initiation or change of atypicalantipsychotics was 24. In 13 instances this occurred duringan in-patient stay with a random or fasting blood glucose testin accordance with the first standard. In 11 instances the initiationor change took place in an out-patient setting; in only 2 wasa blood glucose test recorded. Fifteen of those initiated orchanged also reached 4 months' duration of treatment withinthe audit year. All of those who were in-patients at 4 monthshad a random blood glucose test. None of those reaching 4 months'duration of treatment as out-patients had such a test.

There was a noticeable difference in the rates of testing fordifferent medications. Those stable on olanzapine and clozapinewere more likely to have had tests performed.

All patients who were known to have diabetes were receivingappropriate care for this. However, adherence to the last standardwas only 51%, as patients who had not had a blood test andhad missing data were considered potentially to have diabetes.

Discussion

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Discussion

This medical audit compared our practices with emerging, growingand more definitive evidence about the longer-term side-effectsof antipsychotic treatment. It has been conducted with an awakeningawareness of the lifestyle and physical health needs of thosewith severe and enduring mental illnesses (Connolly & Kelly, 2005). Differences in the surveillance practice for each atypicalantipsychotic are in accordance with previous research (Citrome et al, 2004; Taylor et al, 2004). This might reflect the current lack ofa clear consensus from multiple and differing guidelines onthe necessary monitoring for both primary and secondary care.It is noteworthy that the most common reference used for prescribing,the British National Formulary (http://bnf.org/bnf), suggeststhat olanzapine and clozapine are more liable to cause hyperglycaemia or diabetes as side-effects.

There were large differences between the routine monitoringof blood glucose in in-patient and out-patient settings. In-patientsbenefited from a physical examination with routine physicaltests at the time of admission to the ward. However, a randomblood glucose test was not necessarily a standard and routineminimum requested by the admitting doctor. This concurs withthe findings of Boilson & Hamilton (2003) that for psychiatric admission physical tests are often performed on an ad hoc basis.

Blood glucose testing for out-patients was markedly differentand poor. The main barrier to both the initiation and routinemonitoring of blood glucose as an out-patient was effectivecommunication between services and consistency of information.The standard form of communication between the psychiatristand GP remains a letter and/or telephone conversation. Requestsfor testing of out-patients in letters to the GP may be andwere easily missed. There have been no previous studies investigatingthe physical monitoring of psychiatric out-patients. However,the need for improved communication and coordination of servicesbetween primary and secondary care is well recognised and emphasised by this audit.

Any assumption by psychiatrists that all physical care is theterritory of the GP can hinder the monitoring of psychiatrictreatment. The roles and responsibilities of primary and secondarycare can seem unclear. Emphasis has been placed on the importanceof psychiatrists arranging appropriate monitoring of medicationsthat they are prescribing. Furthermore, advice and informationgiven to the patient about their treatment is essential forgood clinical practice (NICE, 2002b) and aids adherence totreatment and monitoring. Psychiatrists therefore need to workclosely with GPs and their patients to ensure this happens(Connolly & Kelly, 2005).

There is a new emphasis on the need to attend to the long-overlooked physical health of those with severe and enduring mental illness.The new GP contract, the development of registers in primarycare, guidance on clinical indicators (British Medical Association, 2004)and the care programme approach have already given impetus forconsistency and routine monitoring in these areas. Opportunitiesexist to take advantage of this locally by developing a standardand coordinated approach across primary care and mental healthtrusts. With some limited and preliminary evidence that lifestylechanges can reduce the random blood glucose level in thoseon clozapine (Smith & White, 2004), there could also bepotential practical preventive interventions for patients onthese treatments.

References

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