TABLE 3.
Clinical risk factors for melioidosis
| Risk factor | Level of evidence |
|---|---|
| Diabetes mellitus | Between 37 and 60% of patients are diabetic, mainly type 2; case-control and population-based studies in Australia and Thailand give estimated relative risk of 5.9 to 13.1 (111, 114, 299, 415, 417) |
| Thalassaemia | α-Thalassemia trait common in Thailand (44%) but disease less common (8%); case-control studies in Thailand estimate relative risk of 10.2 (415, 417, 464) |
| Aboriginality | Population-based study in Australia estimates relative risk of 2.7 to 8.1, assumed to relate to exposure to soil or water (111, 114, 299) |
| Male gender | All series in Australia, Thailand, Malaysia, and Singapore demonstrate male preponderance (114, 191, 299, 417) |
| Soil/water exposure | Rice farmers constitute 81% of patients in Thailand, relative risk in case-control study estimated at 3.3 (415, 417) |
| Renal disease | Patients with renal impairment or failure comprise 10% of Australian series (111) with relative risk of 3.2 (114); renal disease (renal failure and calculi) associated with increased risk of melioidosis (odds ratio, 2.9) (415, 417) |
| Excessive alcohol consumption | Conflicting evidence; excessive alcohol use documented in 39% of Australian patients, with relative risk of 2.1 to 6.7 in case-control and population-based studies (111, 114, 299), less prevalent in Thai patients (12%) (417) |
| Kava use | Use of Piper methysticum root documented in 8% of Australian series (111) but not associated with pneumonia in case-control study (98) |
| Chronic lung disease | Present in 27% of Australian patients (111), with relative risk of 4.3 (114) |
| Splenectomy | Case studies, often related to thalassemia (196, 334, 464) |
| Aplastic anaemia, febrile neutropenia | Case reports only (273, 417) |
| Chronic granulomatous disease | Two case reports (146, 422) |
| Mycobacterial disease | Case reports of patients with infection with atypical mycobacteria, M. tuberculosis, or M. leprae may suggest common host susceptibility (56, 89, 362, 417) |
| Dengue hemorrhagic fever | Five of 18 pediatric patients in Thailand (334) |
| Neutropaenia | Case report (189) |
| Renal transplantation | Case report, patient also diabetic (224) |
| Systemic lupus erythematosis or steroid use | Case reports, also associated with immunosuppressives (29, 95, 398, 417); steroid-containing herbal remedies documented in up to 10% of Thai patients (415) |
| Glucose-6-phosphatase deficiency | Case reports (417) |
| Hemosiderosis | Case reports (286, 363); one unreported case of pulmonary hemosiderosis secondary to mitral valve disease (B. Currie, unpublished data) |
| Cystic fibrosis | Reports from travelers to areas of endemicity (122, 198, 372, 458) |
| Porphyria cutanea tarda | Subsequent to episode of melioidosis; likely to be an adverse event in response to medication (160) |