title: Differences in the clinical presentation and the frequency of complications between elderly and non-elderly scrub typhus patients.
abstract: Age can affect the clinical features and severity of infectious disorders, such as scrub typhus. We performed this study to examine differences between elderly and non-elderly scrub typhus patients, and to identify risk factors predictive of disease outcomes. This retrospective study included patients admitted to a tertiary hospital with scrub typhus between 2001 and 2011. A total of 615 patients were enrolled in this study, 328 of which were >65 years of age. Of the elderly patients, 46.0% (151/328) experienced at least one complication compared to only 23.0% (66/287) in younger patients. A linear trend was observed between age and complication rates (p=0.002). The most common complication in elderly patients was acute kidney injury (75, 22.9%). Treatment failure was reported in 10 elderly patients (3.0%) compared to one non-elderly patient (0.3%). Mental confusion and dyspnea of clinical manifestations at admission were common in elderly patients. Frequency of fever, rash, and eschar were similar in both groups. The following four factors were significantly associated with severe scrub typhus in elderly patients: (1) white blood cell (WBC) counts>10,000/mm(3) (OR=2.569, CI=1.298-5.086), (2) MDRD GFR<60mL/min (OR=3.525, CI=1.864-6.667), (3) albumin≤3.0g/dL (OR=4.976, CI=2.664-9.294), and (4) acute physiology and chronic health evaluation II (APACHE II) score>10 points (OR=3.304, CI=1.793-60.87). Complications and mortality were more common in elderly patients, often associated with delays in diagnosis and treatment.
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Mi-Ok
authors.initials: MO
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Uh Jin
authors.initials: UJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Joon Hwan
authors.initials: JH
authors.lastname: Ahn
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Seung-Ji
authors.initials: SJ
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Hee-Chang
authors.initials: HC
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea.
authors.forename: Sook-In
authors.initials: SI
authors.lastname: Jung
authors.affiliation: Department of Internal Medicine, Chonnam National University Hospital, Gwang-ju, Republic of Korea. Electronic address: iammedkid@naver.com.
authors.forename: Kyung-Hwa
authors.initials: KH
authors.lastname: Park
mesh_terms: D018806:APACHE; D058186:Acute Kidney Injury / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003221:Confusion / Q000150:complications / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D012285:Orientia tsutsugamushi / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D012612:Scrub Typhus / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology*; D012720:Severity of Illness Index
keywords: Complication; Elderly; Scrub typhus