International Journal of Epidemiology © International Epidemiological Association 1992
Vol. 2 1 , No. 4 Printed in Great Britain
Markers of Risk of Asthma Death or Readmission in the 12 Months Following a Hospital Admission for Asthma JUUAN CRANE, NEIL PEARCE, CARL BURGESS, KATE WOODMAN, BRIDGET ROBSON AND RICHARD BEASLEY
Markers of asthma severity are of relevance both to clinicians who wish to identify patients who are at increased risk of death or readmission, and to epidcmiologists who wish to control for asthma severity in studies of risk factors for asthma deaths, lifethreatening attacks, or hospital admissions. In addition, such markers may provide aetiological clues as to the mechanisms which lead to asthma deaths or lifethreatening attacks. Three recent New Zealand case-control studies1"3 conducted by our group have investigated the association between prescribed asthma drugs and risk of asthma death. The third study examined this issue in patients aged 5-45 years in New Zealand with a hospital admission for asthma (the index admission)
during 1981-1987. The study included a group of patients who died of asthma during the 12 months following the index admission, a group of patients who had a further hospital admission for asthma during the 12 months following the index admission, and a group of patients chosen from all hospital admissions for asthma during the same period. Information was also collected on markers of chronic and acute asthma severity and of psychosocial problems. This permitted an examination of the associations between these factors, and the subsequent risk of asthma death or readmission. These issues have been examined in the present paper, METHODS The design and methods of the original study have been described in detail in a previous publication.3 The study was based on 32 hospitals throughout New
Department of Medicine, Wellington School of Medicine. PO Box 7343, Wellington, New Zealand. 737
Downloaded from http://ije.oxfordjournals.org/ at Fudan University on May 8, 2015
Crane J (Department of Medicine, Wellington School of Medicine, PO Box 7343, Wellington, New Zealand), Pearce N, Burgess C, Woodman K, Robson B and Beasley R. Markers of risk of asthma death or readmission in the 12 months following a hospital admission for asthma. International Journal of Epidemiology 1992; 21: 737-744. A case-control study has previously been reported of asthma deaths in people aged 5-45 years who had a hospital admission for asthma (the index admission) in New Zealand during 1981-1987. The study has been re-analysed to examine the association between markers of asthma severity and risk of asthma death or hospital admission; patients prescribed fenoterol were excluded from this re-analysis because of the previousty reported interaction between fenoterol, asthma severity, and asthma deaths. The re-analysis included 39 patients who died of asthma during the 12 months after their index admission, 226 patients who had areadmisstonfor asthma during the 12 months after their index admission, and 263 controls chosen from all index admissions. An admission in the previous 12 months was the strongest marker of subsequent risk of death (odds ratio (OR) = 3.5,95% confidence interval (CD : 1.8-6.9, P < 0.01), and was also a strong marker of subsequent risk of readmission (OR = 3.0, 95% Cl : 2.1-4.2, P < 0.01); the risk increased with the number of previous admissions. Three or more categories of prescribed asthma drugs was also associated with subsequent death (OR = 1.7, 95% C l : 0.9-3.3, P = 0.13) or readmission (OR = 1.9, 95% C l : 1.3-2.7, P < 0.01); prescribed oral corticosteroids was only weakly associated with subsequent death (OR = 1.3,95% Cl: 0.62.8, P= 0.59), but was more strongly associated with subsequent readmission (OR = 1.9, 95% Cl : 1.2-2.8, P
Vol. 2 1 , No. 4 Printed in Great Britain
Markers of Risk of Asthma Death or Readmission in the 12 Months Following a Hospital Admission for Asthma JUUAN CRANE, NEIL PEARCE, CARL BURGESS, KATE WOODMAN, BRIDGET ROBSON AND RICHARD BEASLEY
Markers of asthma severity are of relevance both to clinicians who wish to identify patients who are at increased risk of death or readmission, and to epidcmiologists who wish to control for asthma severity in studies of risk factors for asthma deaths, lifethreatening attacks, or hospital admissions. In addition, such markers may provide aetiological clues as to the mechanisms which lead to asthma deaths or lifethreatening attacks. Three recent New Zealand case-control studies1"3 conducted by our group have investigated the association between prescribed asthma drugs and risk of asthma death. The third study examined this issue in patients aged 5-45 years in New Zealand with a hospital admission for asthma (the index admission)
during 1981-1987. The study included a group of patients who died of asthma during the 12 months following the index admission, a group of patients who had a further hospital admission for asthma during the 12 months following the index admission, and a group of patients chosen from all hospital admissions for asthma during the same period. Information was also collected on markers of chronic and acute asthma severity and of psychosocial problems. This permitted an examination of the associations between these factors, and the subsequent risk of asthma death or readmission. These issues have been examined in the present paper, METHODS The design and methods of the original study have been described in detail in a previous publication.3 The study was based on 32 hospitals throughout New
Department of Medicine, Wellington School of Medicine. PO Box 7343, Wellington, New Zealand. 737
Downloaded from http://ije.oxfordjournals.org/ at Fudan University on May 8, 2015
Crane J (Department of Medicine, Wellington School of Medicine, PO Box 7343, Wellington, New Zealand), Pearce N, Burgess C, Woodman K, Robson B and Beasley R. Markers of risk of asthma death or readmission in the 12 months following a hospital admission for asthma. International Journal of Epidemiology 1992; 21: 737-744. A case-control study has previously been reported of asthma deaths in people aged 5-45 years who had a hospital admission for asthma (the index admission) in New Zealand during 1981-1987. The study has been re-analysed to examine the association between markers of asthma severity and risk of asthma death or hospital admission; patients prescribed fenoterol were excluded from this re-analysis because of the previousty reported interaction between fenoterol, asthma severity, and asthma deaths. The re-analysis included 39 patients who died of asthma during the 12 months after their index admission, 226 patients who had areadmisstonfor asthma during the 12 months after their index admission, and 263 controls chosen from all index admissions. An admission in the previous 12 months was the strongest marker of subsequent risk of death (odds ratio (OR) = 3.5,95% confidence interval (CD : 1.8-6.9, P < 0.01), and was also a strong marker of subsequent risk of readmission (OR = 3.0, 95% Cl : 2.1-4.2, P < 0.01); the risk increased with the number of previous admissions. Three or more categories of prescribed asthma drugs was also associated with subsequent death (OR = 1.7, 95% C l : 0.9-3.3, P = 0.13) or readmission (OR = 1.9, 95% C l : 1.3-2.7, P < 0.01); prescribed oral corticosteroids was only weakly associated with subsequent death (OR = 1.3,95% Cl: 0.62.8, P= 0.59), but was more strongly associated with subsequent readmission (OR = 1.9, 95% Cl : 1.2-2.8, P
