Screening for delirium and dementia in older hospitalised adults in Zambia

Delirium prevalence and aetiology in older people in hospital or community settings in sub-Saharan Africa (SSA) is largely unknown. Cognitive screening tools designed for high-income countries (HICs) may be inappropriate due to cultural and educational differences, and delirium-specific measures lack validation in this context. The 'Identification and Intervention for Dementia in Elderly Africans' (IDEA) screen is a low-literacy tool developed and validated for dementia and delirium screening in Tanzania and Nigeria. This study aims to determine the prevalence and aetiology of delirium and dementia in older hospitalised patients in Zambia and to assess the utility of the IDEA screen for identification of major cognitive impairment in this setting. This was a blinded 4-month validation study which took place February-June 2015. Consecutive inpatient admissions of a rural mission hospital aged >= 60 years were administered the IDEA screen onadmission. Individuals were evaluated for dementia or delirium based on clinical examination, notes review and the Confusion Assessment Method. Delirium aetiological factors were recorded and classified (infectious/non-infectious). Of 136 patients recruited, dementia, delirium and major cognitive impairment were identified in 37 (27.2%), 45 (33.1%) and 62 (45.6%) respectively. Diagnostic accuracy of the IDEA screen for dementia and delirium was 0.661-0.795 (AUROC). Of those with delirium, 18 (40%) were classified infectious and 26 (57.8%) were classified non-infectious aetiologies. Dementia and delirium prevalence in older Zambian inpatients is comparable tohigh-income countries. The IDEA screen ispotentially clinically useful in this setting though diagnostic accuracy was lower than in initial validation studies. Non-infectious diseases are more highly represented amongst delirium precipitants than anticipated.