Bronchiectasis in Auckland, New Zealand: Ethnic differences in severity

Introduction: Bronchiectasis is more prevalent in Maori and Pacific Islanders (PI) than Europeans. The aim of this study was to evaluate differences in severity and microbiology between ethnicities. Methods: Records of 250 patients (66% female, mean age 62yrs, FEV1% predicted 64.6%) attending the bronchiectasis clinic at Auckland District Health Board were retrospectively reviewed. Demographic and clinical variables were recorded. Ethnicity was compared to NZ Department Statistics 2006 census data for central Auckland. Results: PI (23%) and Maori (12%) are over-represented in this cohort; European (44%) and Asian (16%) under-represented. Mean FEV1 %predicted was higher in Europeans (70.7%) than Maori (63%) and PI (54%), p <0.0001 and remained so when corrected for smoking status p<0.0001. Similar statistically significant differences were seen in FVC %predicted. Maori patients were younger (mean age 56yrs) than PI (60yrs) and Europeans (66yrs), p=0.02. There was a trend to later diagnosis in Maori and PI compared to Europeans. 124 patients had at least one sputum sampled that year with Haemophilus 29%, Pseudomonas 13.7%, Aspergillus 4.8%, Pneumococcus 2.4% and non tuberculous mycobacteria 2.4%. There was no significant difference in sputum microbiology by ethnicity. Conclusions: Maori and PI are over-represented in the bronchiectasis clinic and tend to be younger with more severe disease than other ethnicities. Disease severity is independent of smoking status, microbiology and gender suggesting other factors such as genetic susceptibility or socioeconomic status influence outcome.