Sharma A, et al. - In this case–control study, researchers used medical chart review to determine the pattern and duration of heroin use and logistic regression to investigate the links between heroin use and AA-type kidney amyloidosis among 38 patients with biopsy-confirmed kidney AA amyloidosis and 72 matched control individuals without this condition from two large hospital systems in Seattle, Washington. In the Pacific Northwest, a strong association was reported between injection heroin use and kidney AA amyloidosis. As etiologic factors of this progressive kidney disease, the possible importance of unique aspects of heroin use, in particular geographic regions or frequent associated soft-tissue infections, was indicated.