Relationship of peak expiratory flow rate with mortality and ischaemic heart disease in elderly Australians

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Abstract
Objective To evaluate the relationships of mortality and ischaemic heart disease (IHD) with peak expiratory flow rate (PEF) in the elderly. Design Prospective study with median follow‐up of 83 months. Setting Dubbo, a New South Wales country town (population, 30500). Subjects Non‐institutionalised residents born before 1930 (i.e., aged 60 years and over at study entry). Participation rate was 73% (1235 men and 1570 women). Main outcome measures Baseline demographic, psychosocial and standard cardiovascular risk factors, including PEF; all‐causes mortality, IHD mortality and IHD events (hospitalisations with any manifestation of IHD) by tertile of PEF. Results More subjects with PEF in the lowest tertile (I) had a past history of respiratory disease, were current cigarette smokers and were taking antihypertensive drugs. During follow‐up, 321 men (26%) and 252 women (16%) died. All‐causes mortality was three (men) to four (women) times higher for those in PEF tertile I than for those in tertile III. IHD mortality and IHD events showed similar trends. In a proportional hazards model adjusted for age, height, smoking status and other risk factors or confounders, the hazard ratios (95% confidence interval) for men in PEF tertile I versus tertile III were: all‐causes mortality, 1.62 (1.14–2.30); IHD mortality, 1.75 (0.96–3.20); and IHD events, 1.12 (0.82–1.53). For women, respective hazard ratios were 1.92 (1.23–3.00), 2.58 (1.24–5.39), and 1.16 (0.83–1.63). Conclusions We confirm an independent, inverse relationship between PEF and all‐causes and IHD mortality. The data suggest a potential benefit for coronary risk factor management in subjects with existing airways disease and further support the case for antismoking programs.