The usefulness of appetite and energy intake-based algorithms to assess treatment effect of a bacterial infection: An observational prospective study

BACKGROUND The diagnosis of infectious diseases and the duration of antibiotic therapies are generally based on empirical rules. Studies implicate that the use biological markers can be used as a reliable method to shorten antibiotic therapies. The return of appetite is a clinical aspect of recovery from an infection that may be used to guide antibiotic therapies. OBJECTIVE To compare changes in appetite and daily energy intake with changes in CRP-levels in patients recovering from an infection. DESIGN Observational study using a consecutive sample of patients admitted to the unit for infectious diseases at a University Hospital in Sweden, February to April 2014. Energy intake, CRP-levels and appetite were recorded daily. Energy intake was calculated using estimated energy contents. Appetite was measured using a validated visual analogue scale. Changes in daily energy intakes, CRP-levels and appetite were analysed. RESULTS 49 patients (51% men) were included in the analysis from the overall population of 256 patients. During the length of the stay (median 3 days) CRP-levels fell in 92% of the patients (p<0.001), daily energy intake increased in 73% (median intake +6381 kJ/day, p<0.001) and appetite increased in 55% of the patients (p = 0.181). VAS-estimations of appetite augmented in 55%, decreased in 41% and were equal in 5% of the patients (p = 0.181). There was a non-significant difference in the within-subject variances in daily energy intake between female and male patients but not in other subsets. CONCLUSIONS We found a significantly increase in the daily energy intake but not in self-estimated appetite in patients recovering from an infection. We suggest measuring the daily energy intake as a complement to other biological and clinical markers among inpatients to assess treatment effect.