ALL-CAUSE MORTALITY IN PATIENTS FOLLOWING FIRST
ADMISSION FOR HEART FAILURE IN NEW ZEALAND R N Doughty, S P Wright*, G
Gamble, N Sharpe Dept of Medicine, University of
Auckland Background: Heart failure is a
major public health problem, characterised by frequent hospitalisation and a
poor prognosis. Mortality statistics in heart failure (HF) are often limited
due to omission of HF from death certification. This study examines the
survival of patients with heart failure after their first admission with heart
failure using a national hospital admissions database from 1988 to 1997 in New
Zealand. Methods: National statistics for hospital
admissions with heart failure were obtained from the New Zealand Health
Information Service using ICD-9 codes for heart failure both as a primary
diagnosis or a secondary diagnosis associated with either ischaemic, rheumatic
or valvular heart disease. Each patient was identified by a unique patient
identifier. Index hospital admission and all-cause mortality statistics were obtained
from the same source, allowing the survival of all patients after their index
admission to be accurately ascertained. Results: There were 55,417 first
admissions for HF over 10 years. The median age at death was 79 years (IQR 71,
85). 80% of deaths were attributable to cardiac causes; 17% of these were
stated to be due to heart failure. HF was recorded as a contributing diagnosis
in only 13% of death certificates. The crude in-hospital mortality during first
admissions with HF was 11.2% in 1988 and 8.5% in 1997 (p=0.001). The overall
age standardized mortality was 6.7% in patients <75 years and 14% in
patients >= 75 years.
All-cause mortality at 30 days, 6 months and 1 year after index HF admission
was significantly higher in the over-75 year age group, as shown in the table
below. Mortality <75
years >=75
years p-value 30
day 8.8% 15.8% 0.001 6
month 17.5% 30.4% 0.001 1
year 23.1% 38.9% 0.001 Conclusions: The contribution of heart failure as an underlying diagnosis
is under-reported in heart failure patients. The case fatality rate in heart
failure is strongly associated with age, and appears to be increasing.
In-hospital mortality rates appear to be decreasing. This may reflect admission
of patients at an earlier stage of their disease process or true mortality
reductions associated with medical therapy.
