A cardiovascular extension of the Health Measurement Questionnaire

OBJECTIVE: To investigate the psychometric properties of a cardiovascular extension of an existing utility-based quality of life questionnaire (Health Measurement Questionnaire). The new instrument has been named the Utility Based Quality of life--Heart questionnaire, or UBQ-H. DESIGN: Explored the test-retest reliability, construct validity, and responsiveness of the UBQ-H. PATIENTS: A sample of 322 patients attending cardiac outpatient clinics were recruited from two large metropolitan teaching hospitals. A second sample of 1112 patients taking part in the LIPID trial was also used to investigate the validity and responsiveness of the UBQ-H. RESULTS: Ninety per cent of all UBQ-H questionnaires were returned, and item completion rates were high (median of less than 1% missing or N/A answers). Cronbach's alpha measure of internal consistency for the scales ranged between 0.79- 0.91, and each item was also most strongly correlated with its hypothesised domain than alternative domains. The intra-class test- retest reliability of the UBQ-H scales ranged from 0.65 to 0.81 for patients with stable health. Results supported the construct validity of the UBQ-H. The UBQ-H was significantly correlated with other information on quality of life (for example, General Health Questionnaire) as anticipated. The instrument was able to distinguish between contrasted groups of patients (for example, with versus without symptoms of dyspnoea, prior myocardial infarction versus none, etc), and was responsive to changes in health associated with adverse events requiring hospitalisation. CONCLUSIONS: The modifications made to the Health Measurement Questionnaire has resulted in an assessment designed for cardiovascular patients that has proved to be both reliable and valid.

Identifying Variables Responsible for Data not Missing at Random

parameter bias, effect size, not missing at random, mean and covariance structural models,

The effects of lowering LDL cholesterol with statin therapy in people at low risk of vascular disease: meta-analysis of individual data from 27 randomised trials

<p>Background: Statins reduce LDL cholesterol and prevent vascular events, but their net effects in people at low risk of vascular events remain uncertain.</p> <p>Methods: This meta-analysis included individual participant data from 22 trials of statin versus control (n=134 537; mean LDL cholesterol difference 1·08 mmol/L; median follow-up 4·8 years) and five trials of more versus less statin (n=39 612; difference 0·51 mmol/L; 5·1 years). Major vascular events were major coronary events (ie, non-fatal myocardial infarction or coronary death), strokes, or coronary revascularisations. Participants were separated into five categories of baseline 5-year major vascular event risk on control therapy (no statin or low-intensity statin) (<5%, ≥5% to <10%, ≥10% to <20%,≥20% to <30%, ≥30%); in each, the rate ratio (RR) per 1·0 mmol/L LDL cholesterol reduction was estimated.</p> <p>Findings: Reduction of LDL cholesterol with a statin reduced the risk of major vascular events (RR 0·79, 95% CI 0·77—0·81, per 1·0 mmol/L reduction), largely irrespective of age, sex, baseline LDL cholesterol or previous vascular disease, and of vascular and all-cause mortality. The proportional reduction in major vascular events was at least as big in the two lowest risk categories as in the higher risk categories (RR per 1·0 mmol/L reduction from lowest to highest risk: 0·62 [99% CI 0·47—0·81], 0·69 [99% CI 0·60—0·79], 0·79 [99% CI 0·74—0·85], 0·81 [99% CI 0·77—0·86], and 0·79 [99% CI 0·74—0·84]; trend p=0·04), which reflected significant reductions in these two lowest risk categories in major coronary events (RR 0·57, 99% CI 0·36—0·89, p=0·0012, and 0·61, 99% CI 0·50—0·74, p<0·0001) and in coronary revascularisations (RR 0·52, 99% CI 0·35—0·75, and 0·63, 99% CI 0·51—0·79; both p<0·0001). For stroke, the reduction in risk in participants with 5-year risk of major vascular events lower than 10% (RR per 1·0 mmol/L LDL cholesterol reduction 0·76, 99% CI 0·61—0·95, p=0·0012) was also similar to that seen in higher risk categories (trend p=0·3). In participants without a history of vascular disease, statins reduced the risks of vascular (RR per 1·0 mmol/L LDL cholesterol reduction 0·85, 95% CI 0·77—0·95) and all-cause mortality (RR 0·91, 95% CI 0·85—0·97), and the proportional reductions were similar by baseline risk. There was no evidence that reduction of LDL cholesterol with a statin increased cancer incidence (RR per 1·0 mmol/L LDL cholesterol reduction 1·00, 95% CI 0·96—1·04), cancer mortality (RR 0·99, 95% CI 0·93—1·06), or other non-vascular mortality.</p> <p>Interpretation: In individuals with 5-year risk of major vascular events lower than 10%, each 1 mmol/L reduction in LDL cholesterol produced an absolute reduction in major vascular events of about 11 per 1000 over 5 years. This benefit greatly exceeds any known hazards of statin therapy. Under present guidelines, such individuals would not typically be regarded as suitable for LDL-lowering statin therapy. The present report suggests, therefore, that these guidelines might need to be reconsidered.</p&gt