Background Hospital admission rates for chronic obstructive pulmonary disease (COPD) are known to be strongly associated with population factors. Primary care services may also affect admission rates, but there is little direct supporting evidence.

Objectives To determine associations between population characteristics, diagnosed and undiagnosed COPD prevalence, primary healthcare factors, and COPD admission rates primary care trust (PCT) and general practice levels in England.

Design, setting, and participants National cross-sectional study (53,676,051 patients in 8,064 practices in 152 English PCTs), combining data on hospital admissions, populations, primary healthcare staffing, clinical practice quality and access, and prevalence.

Main outcome measures Directly and indirectly standardised hospital admission rates for COPD, for PCT and practice populations.

Results Mean annual COPD admission rates per 100 000 population varied from 124.7 to 646.5 for PCTs and 0.0 to 2175.2 for practices. Admissions were strongly associated with population deprivation at both levels. In a practice-level multivariate Poisson regression, registered and undiagnosed COPD prevalence, smoking prevalence and deprivation were risk factors for admission (p<0.001), while healthcare factors- influenza immunisation, patient-reported access to consultations within two days, and primary care staffing, were protective (p<0.05).

Conclusion Associations of COPD admission rates with deprivation, primary healthcare access and supply highlight the need for adequate services in deprived areas. An association between admission rates and undiagnosed COPD prevalence suggests that case-finding strategies should be evaluated. Of the COPD clinical quality indicators, only influenza immunisation was associated with reduced admission rates. Patients' experience of access to primary care may also be clinically important.