Dementia and Poor Surgical Outcomes: Reinventing the Wheel or Providing Empirical Evidence?

The increasing prevalence of dementia and its growingworldwide impact on public health and resources are wellestablished [1, 2]. This article [3] is a large retrospectivecohort study comparing the morbidity of surgery in 18,923patients with dementia with that of 75,692 (age- and sex-matched) controls without dementia that had surgery. Thestudy showed that (1) preoperative morbidity and averagelength of hospital stay were higher in the dementia group;(2) 30-day mortality, overall complications, and speci-cally stroke, urinary tract infection, renal failure, pneu-monia, and septicaemia were higher in the group withdementia; this was signicant after adjusting for severalfactors, including coexisting medical conditions; (3) caringfor dementia patients is expensive!So, what’s new? Dementia as a preoperative risk factoris well known and these ndings could have been predictedby most readers. In addition, studies of this nature do notanalyse or explore ‘‘patient-level’’ data and can thereforedemonstrate only a global view of the problem whileignoring the complexities of the interventions, the under-lying pathologies, and the decision-making processesinvolved in the management of the individual patient.While academicians may debate over the associative orcausativeinuenceofdementiaandthemechanistic theorieslinking dementia and poor outcomes, what studies like thisprovide for clinicians is an estimate of risk, i.e., extent of theincrease in morbidity that is attributable to dementia. Theseestimates can be used by surgeons and patients (with familymembers) in making informed decisions about the benetsand risks of surgery. They also help in targeting appropriatepreventativestrategiesaimedtoreduceriskofcomplicationsindementiapatients.Lastly,theseestimatesarealsoofvalueto health-care providers and policy makers to determineappropriate resource provision in a world where health careis burdened by the increasing prevalence of age-relateddementia and constrained by nancial limitations.An important take home message from this study is theincreased risk of 30-day mortality. This is, of course,inuenced by the kind of surgery, coexisting medicalconditions, and underlying pathology for which surgery iscontemplated. Also, how this risk is interpreted and com-municated to the patient is crucial to how clinical decisionsare made. Taking ‘‘in-hospital mortality’’ as an outcomeand extrapolating the numbers from Table 2, the data couldbe represented in one of two ways: ‘‘Surgery wouldincrease the risk of in-hospital death in a dementia patientby 0.85 % (from 1 to 1.85 %)’’ or ‘‘The presence ofdementia would increase the relative risk of in-hospitaldeath by 85 %.’’ Although both statements refer to thesame underlying data set, the description of risk in absoluteterms (i.e., the former statement) provides a clearerunderstanding of the issue and should be encouraged.References