Introduction Previous studies have assessed the relationship between body mass index (BMI) and healthcare use in primary care settings but have been limited to individuals with pre-defined diseases or those with a recorded diagnosis of malnutrition.^1–3 This study using data from The Health Improvement Network (THIN) database (UK) aimed to examine GP-related healthcare use and hospital admissions according to two BMI categories (underweight and normal weight) across all individuals registered to GP practice.

Methods Two cohorts of individuals registered with GPs were randomly selected from the THIN database (Cohort 1 BMI ≤19.9 kg/m² n2632, Cohort 2 BMI 20.0 to ≤24.9 kg/m² n2632). Cohorts were matched for age (52 y (22.4)), gender (81% female) and GP practice. Individuals were included if they had at least two BMIs recorded from May 2010 to May 2011 and were registered for at least 12 months. Individuals were excluded if they; were living in institutions, had conditions affecting weight for example, oedema, had a BMI <13.0 kg/m², or receiving palliative/end of life care. GP-related healthcare use (practice visits, home visits, out of hours visits, telephone consultations) and hospital admissions over 1 year were retrieved using read codes and locate flags; and a simple cost analysis was undertaken using unit costs.⁴

Results A significantly greater proportion of individuals with a BMI ≤19.9 kg/m² had at least one; home, out of hours visit or telephone consultation with the GP practice (Abstract OC-038 table 1), and had significantly more practice visits than individuals with a BMI 20.0 to ≤24.9 kg/m² (8.5 vs 8.3 visits respectively p=0.022 Mann–Whitney U). Similar results were seen for hospital admissions, with a significantly greater proportion of individuals with a BMI ≤19.9 kg/m² being admitted to hospital (Abstract OC-038 table 1). Compared to individuals with a BMI 20.0 to ≤24.9 kg/m², mean GP contact costs per person per year were increased by £29.54 and admissions by £34.62 per year.⁵

Conclusion This study using data from THIN shows that individuals registered with their GP, with a low BMI (≤19.9 kg/m²) use significantly more healthcare resources than those with a normal BMI (20.0 to ≤24.9 kg/m²). The contribution of disease types and severity, social and nutrition-related factors needs to be further evaluated.

Competing interests K Ashman Employee of: Nutricia, A Cawood Employee of: Nutricia, R Stratton Employee of: Nutricia.

References 1. Martyn CN, et al. Clin Nutr 1998;17:119–23.

2. Edington J, et al. Proc Nutr Soc 1999;58:655–61.

3. Guest JF, et al. Clin Nutr 2011;30:422–9.

4. Curtis L. Unit cost of health and social care. 2010.