A L McLeod, L Brooks*, V Taylor#, A Wylie*, P F Currie*, N G Dewhurst*
Department of Cardiology Ninewells Hospital Dundee; *Department of Cardiology Perth Royal Infirmary Perth;
#Health Centre Dalkeith Midlothian
Correspondence to: Dr Andrew McLeod, Specialist Registrar in Cardiology, Department of Cardiology, OPD3, New Royal Infirmary of Edinburgh at Little France, Edinburgh E-mail: a.mcleod@ed.ac.uk
SMJ 2005 50(2): 54-56
Abstract
Background: Secondary prevention of coronary artery disease is effective in reducing morbitiy and mortality. Our aim was to assess lipid management following non-attendance to a hospital based secondary prevention clinic Methods: Data were collected over 5 years on statin usage and total cholesterol levels for patients with coronary artery disease following attendance at a cardiac nurse led outpatient clinic. Lipid levels were taken from a central laboratory database, for both patients discharged from clinic and non-attenders. Results: From 935 inpatients discharged from hospital, 248 (29%) defaulted from outpatient follow up. Lipid lowering drug usage was similar (72% vs. 74% for non-attenders, p=NS). Attenders at the nurse led outpatient clinic were more likely to achieve a total cholesterol <5mmol/L at discharge than non-attenders (70% vs. 43%; p<0.001), with a lower mean total cholesterol (4.75±0.06 mmol/L vs. 5.33±0.08 mmol/L; p<0.001). Non-attenders subsequently had a greater number of cholesterol measurements than those who were discharged from the hospital based clinic (range 0-12, c2 23.8 on 12df, p<0.05). Lipid profiles in hospital non-attenders remained inferior with fewer achieving a total cholesterol <5mmol/L (61% vs. 78%; p<0.001), and having greater mean total cholesterol levels (4.85±0.06 mmol/L vs. 4.52±0.05 mmol/L; p<0.001). Conclusions: Patients defaulting from hospital follow up have higher total cholesterols with fewer at target level compared to attenders. Though non-attenders receive subsequent lipid measurement, inferior lipid profiles persist compared to patients who completed hospital follow up to be discharged. Further implementation strategies are needed with regard to lipid management in this patient group.
Key words: Cholesterol, coronary disease, non-attender, secondary prevention
Introduction
The identification of coronary heart disease and future healthcare provision is a main priority in the National Service Framework (Dept of Health 2000)1 and with multidisciplinary coronary heart disease management programs, the process of care has been shown to improve with reduced hospital admissions, improved quality of life and a reduction in mortality.2,3 Lipid lowering agents have been shown to reduce both coronary mortality and non-fatal coronary events mortality for both primary and secondary prevention.4-12 Statin use is increasing though there remains considerable scope for improving secondary prevention of coronary artery disease.13-16 Non-attenders to secondary prevention clinics constitute a group that may receive sub-optimal measures to reach targets. In this study we analysed the effect on lipid management of patients with coronary heart disease who did not attend or defaulted from follow up at a hospital based, nurse led cardiac outpatient clinic.
Methods
A total of 935 patients with coronary heart disease received a baseline visit by a specialist cardiac rehabilitation nurse during inpatient hospital stay, and were invited to attend a nurse led outpatient follow up clinic. A coronary heart disease cardiac rehabilitation and risk dataset, initiated at the end of 1996 was completed. The patients were given formal justification of purpose of the data collection with agreement at the time of initial review by the cardiac nurse. Index diagnoses were angina, post myocardial infarction and revascularisation. Data were collected prospectively over five years with retrospective analysis. In addition to patient demographics information was prospectively collected regarding statin usage and total cholesterol concentrations for both attenders and nonattenders. Statin usage was assessed by direct questioning by the nurse practitioner and review of prescriptions. Baseline data was recorded at the time of hospital inpatient discharge. Data for attenders were recorded at discharge following the final outpatient clinic appointment at twelve months. Data collection for non-attenders were recorded either at the time of their last visit to the outpatient clinic before defaulting or at hospital inpatient discharge for those who never attended. The final total cholesterol levels recorded were taken from a central laboratory database, serving both primary and secondary care within Tayside (Fountain Information Service version 3.4).
Analysis
Quantitative variables are expressed as percentage and mean±standard error of the mean. Data was analysed where appropriate by Student’s t-test, Fisher’s exact test, Chisquared and ECTA (Exact Contingency Table Analysis). Statistical significance was taken at the 5% level.
Results
A total of 935 patients (71% male) were entered into the database at hospital discharge of which 69 died. Of the index diagnoses 185 (20%) had angina, 536 (57%) patients were post myocardial infarction, 157 (17%) had undergone coronary artery bypass grafting and 58 (6%) had angioplasty. Mean age was 63.1±0.3 years (range 33-88).
Two hundred and forty-eight(29%) were non-attenders of which 182(73%) were male. Mean age of the non-attenders was 60.1±0.6 years (range 33-81 years). There was no significant difference between attendance/nonattendance and index diagnosis (26.5% angina, 27.5% post myocardial infarction, 29.9% coronary artery bypass grafting and 24.1% angioplasty, p=NS). 34% of non-attenders did not appear for the initial clinic appointment with 37% defaulting after the first visit.
A comparison between the attenders and non-attenders with regard to lipid management is shown in Table I. Lipid lowering usage was similar with 72% for attenders and 74% for non-attenders (p=NS). The proportion of attenders with a total cholesterol <5mmol/L at clinic discharge was significantly greater than non-attenders at their last visit (70% vs. 43%; p<0.001). Mean total cholesterol for attenders at clinic discharge was significantly less than nonattenders’ final cholesterol measurement (4.75±0.06 mmol/L vs. 5.33±0.08 mmol/L; p<0.001).
Cholesterol level either as outpatients or via primary care could not be traced in 15(6%) of discharged clinic patients and 21(9%) of the non-attenders. There was however a significantly greater number of subsequent total cholesterol measurements performed on hospital non-attenders compared to those who were discharged from outpatient follow up (range 0-12, c2 23.8 on 12df, p<0.05). Patients who were discharged from the nurse led clinic on statins had a significantly greater number of subsequent total cholesterol measurements compared to those not on statins (range 0-12, c2 32.2 on 12 df, p<0.05). There was no significant difference in the number of cholesterol measurements for the non-attenders on statins versus those not on statins (range 0-12, c2 19.7 on 12df, p=NS).
Fifty-nine per cent of patients had their final total cholesterol checked via primary care with 26% via secondary care (15% unknown source). Of patients discharged from hospital follow up a significantly greater proportion had a final total cholesterol level <5mmol/L compared with nonattenders (78% vs. 61%; p<0.001). The final total cholesterol was significantly lower for patients completing hospital follow up than non-attenders (4.52±0.05 mmol/ L vs. 4.85±0.06 mmol/L; p<0.001).
Discussion
This study has shown that patients who do not attend or default from a hospital based secondary prevention clinic have higher total cholesterol levels compared to those who complied with follow up arrangements. Though a greater proportion of non-attenders eventually reach target cholesterol levels, the proportion was significantly less compared to those completing hospital follow up.
The risk of subsequent non-attendance at the secondary prevention clinic reinforces the importance of commencing statins in hospital. Previous studies have suggested that statin prescription in hospital not only improves outcome but also increases compliance.9,17-21 In MIRACL (myocardial ischaemia reduction with aggressive cholesterol lowering) Atorvastatin treatment in patients with non-ST elevation acute coronary syndromes was commenced within four days of presentation was associated with a 16% relative risk reduction for the combined end point of death, non-fatal myocardial infarction, cardiac arrest or worsening angina requiring hospitalisation.9 Jackevicius et al reported that even after starting statin therapy patients may stop medication and after two years only 40.1% adhering to statins following acute coronary syndromes, 36.1% for chronic coronary artery disease and 25.4% for primary prevention.22
In our study 34% of patients did not even attend the first clinic visit with 37% not attending the second and subsequent appointments. Clinic follow up visits remain key in measuring total cholesterol levels and titrating statin dose. This is reflected by the significantly greater proportion of patients reaching target total cholesterol levels when attending outpatient follow up. Attendance was independent as to whether the patient had angina, a recent myocardial infarction or had undergone revascularisation.
It is striking that only 36(7%) patients had no subsequent cholesterol measured. Patients who did not attend hospital follow up had cholesterol measured more frequently irrespective of statin prescription. The greater number of measurements may reflect primary care management prompted by inferior lipid profiles in non-attenders. It is not certain, however, whether these samples originated from primary care or followed a further hospital admission, however the final cholesterol measurement was taken form primary care in two-thirds of patients. It is tempting to speculate that the non-attenders are at a higher risk and are therefore more likely to be readmitted.
Our data suggests that in relation to the final total cholesterol measurement, a significantly greater proportion of patients completing hospital follow up achieved target compared with the non-attenders. Though prescription of statins is increasing in primary care13,16,23 delayed and suboptimal dose titration may occur in the non-attender group despite repeated lipid measurements. Poor compliance with medication may also be an influencing factor in the group who defaulted from follow up.
The data shows that further implementation strategies are needed to initiate statin therapy, titrated dose and achieve target cholesterol. With the new GP contract specifically identifying targets for chronic disease management, there may be further incentives for addressing lipid management in patients with coronary heart disease.
Conclusions
With a significant risk of non-attendance at secondary prevention clinics it is important that statin therapy is commenced in hospital. Patients not attending hospital follow up have significantly higher total cholesterol levels and fewer achieve target levels compared to attenders. Though non-attenders receive repeat lipid measurement their inferior profiles persist compared to patients who completed hospital follow up. Further implementation strategies are needed with regard to lipid management in this potentially high risk patient group.
ACKNOWLEDGEMENTS: This work was conducted with the support of the Tayside Clinical Governance Committee. We are indebted to Dr F Daly who provided statistical input (Senior Lecturer, Dept. of Medicine, Ninewells Hospital and Medical School, Dundee, Scotland,UK).
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