Hospitalisation and surgery: are there hidden cognitive consequences? Evidence from The Irish Longitudinal study on...

the dramatic shift in the global population demographic has led to increasing numbers of older people undergoing hospitalisation and surgical procedures.

to determine whether hospitalisation or hospitalisation with surgery under general anaesthesia is associated with poorer cognitive performance in adults over the age of 50.

cognitive function in the domains of global cognition, memory and executive function was assessed in 8,023 individuals at waves 1 and 2 of The Irish Longitudinal Study on Ageing (TILDA), 2 years apart. Mixed-effects models were used to investigate the hypothesis after adjustment for risk factors for cognitive decline and potential confounders.

during the 12 months preceding wave 1, 472 participants were hospitalised (mean age 67.0, 54.9% female) and a further 560 participants (mean age 64.6, 52.1% female) were hospitalised and underwent surgery with general anaesthesia; 6,938 (mean age 63.5, 54.5% female) were not hospitalised. There was a 14% higher error rate (IRR[95% CI] = 1.14[1.06, 1.22]) in the MMSE in the hospitalisation group and a 6% higher error rate (IRR[95% CI] = 1.06[0.99, 1.13]) in the surgery group compared to those with no hospitalisation. Poorer cognitive performance in the memory tasks was evident in both hospitalisation and hospitalisation with surgery groups (immediate recall: [95% CI] = -0.13 words[-0.22,-0.04] versus -0.13 words[-0.21,-0.04] and delayed recall: -0.20 words[-0.33,-0.06] versus -0.20[-0.32, -0.07]) compared to those with no hospitalisation. Increased error in the time-based prospective memory task was observed in the hospitalisation group and the surgery group (OR[95% CI] = 1.32[1.08, 1.60] versus 1.29[1.07, 1.55]).

hospitalisation and hospitalisation with surgery and general anaesthesia are associated with poorer global and domain specific cognitive performance.