3.1.6 Compliance

Compliance to ONS is usually high and depends on the patients’ and ONS characteristics.

• A prospective multicentre observational study conducted in France between March 2013 and January 2016 (n = 191) involving malnourished individuals aged 70 and older living at home found that the average compliance with ONS after one month was 83.5%. Specifically, 48.1% of participants reported consuming the full prescribed amount, 28.6% consumed between 75% and 99%, and 12.8% consumed between 50% and 74%. Only 10.5% reported consuming less than half of the recommended ONS. The study concluded that a higher intake of energy and protein from ONS was linked to a lower risk of hospitalisation and reduced healthcare costs. ⁶⁴
• A systematic review from 2012, investigating whether patients’ compliance to ONS (amount consumed relative to amount prescribed) varied according to healthcare setting, ONS type, volume or duration and patient characteristics such as age or condition found that:¹⁴³
  • Overall pooled mean compliance to ONS was 78.2% (SD 15, range 37-100%; n = 52 studies) and in 62% of studies compliance was ≥ 75%;
  • Mean percentage compliance to ONS was 80.9% in studies in the community (included patients attending hospital outpatients, residents in care homes and free-living individuals) (SD 13, n = 33 studies), 67.2% in studies in hospitals (SD 12, n = 10) and 80.7% (SD 8, n = 3) in studies in multiple settings (included patients in both hospital and community);
  • Energy density was the main ONS-related factor positively associated with compliance (r² = 0.093) with significantly higher mean percentage compliance to ONS containing ≥ 2 kcal/ml than ONS with 1-1.3 kcal/ml or 1.5 kcal/ml (91% vs 77% vs 78% respectively, p < 0.05);
  • Duration of ONS intervention or volume of ONS prescription did not appear to be correlated with compliance (duration: r² = 0.055, p = 0.124, n = 44 studies; volume: r² = 0.0002, p = 0.774, n = 39 studies);
  • Compliance was negatively associated with age (r² = 0.148, p = 0.01, n = 44 studies), but no significant difference in compliance to ONS was found in different patient groups (p = 0.130);
  • Compliance to ONS was positively associated with greater ONS energy intake (r² = 0.106,p = 0.024, n = 48 studies) and total energy intakes (energy from food plus ONS) (r² = 0.307, p = 0.002, n = 29 studies).

• The results of this SLR differ from those from Elia et al., however the studied populations were different. Studies of surgical patients were excluded in Bally et al., except where there was a mixed cohort of medical and surgical patients where the results for the medical patients were not reported separately.
• A 2017 review (n =28619) that included a broader range of patients, including those in intensive care units and surgical settings, as well as various forms of nutritional support, including parenteral nutrition, did not find a positive association between nutritional support and clinical outcomes in hospitalised adults at nutritional risk.¹⁴⁴
• Conversely, in a 2019 review by Gomes et al., 27 randomised controlled trials (n = 6803) examined the impact of nutritional support on clinical outcomes in malnourished or at-risk medical inpatients found that, despite heterogeneity variability in study quality and methodology, nutritional support was linked to improved survival and lower rates of unplanned hospital readmissions. The included studies investigated various forms of nutritional support, such as dietary counselling, modifications in nutritional care practices, food fortification, additional snacks, oral nutritional supplements, and enteral tube feeding, but excluded parenteral nutrition.¹⁴⁵
• A Cochrane review on the effectiveness and efficacy of nutritional therapy reviewed nine randomised controlled trials and two meta-analyses but gave non-conclusive results whether re-admissions within 30 days from hospital discharge could be reduced by nutritional therapy.¹⁴⁶ Nutritional therapy included oral/enteral/ and parenteral nutrition therapy but excluded dietary advice/counselling as the sole intervention. It also included immuno-nutrition which is outside the scope of this document and therefore has not been discussed. Interestingly the review considered 16 studies to specifically determine the economic benefits of nutrition support in hospitalised patients and concluded that all the studies analysed consistently found that nutritional interventions provide economic benefits in terms of savings and cost-effectiveness. The authors stated that this conclusion should be interpreted in light of the limited strength of the evidence available. The review also included two community studies and concluded that nutritional intervention may be cost-effective in selected sub-groups of outpatients; however, the evidence-base is limited.¹⁴⁶