Serum Phosphate Predicts Early Mortality among Underweight Adults Starting ART in Zambia: A Novel Context for Refeeding Syndrome?

Table 2

Pre-treatment serum phosphate and odds ratios of death prior to 12 weeks among study participants, stratified by BMI (𝑛=305)*.

BMI range	Patients at risk (deaths at 12 weeks)	Median pretreatment serum phosphate, mmol/L (IQR)	Odds ratio of mortality, per 0.1 mmol/L decrease in pre-treatment serum phosphate (95% CI)**	𝑃 value
All patients	305 (40)	1.2 (1.0, 1.4)	1.13 (1.00, 1.28)	0.06
≥18.5 kg/m^2	161 (12)	1.2 (1.0, 1.4)	0.96 (0.76, 1.21)	0.74
<18.5 kg/m^2	144 (28)	1.3 (1.1, 1.4)	1.24 (1.05, 1.47)	0.01
<17 kg/m^2	86 (21)	1.3 (1.1, 1.4)	1.25 (1.02, 1.52)	0.03
<16 kg/m^2	49 (13)	1.3 (1.1, 1.4)	1.06 (0.79, 1.42)	0.70

∗Two patients with known vital status at 90 days (one alive and one deceased) were missing baseline BMI and excluded from the analysis.
**Adjusted for sex, age, and CD4⁺ lymphocyte count at ART initiation.
The effect of lower serum phosphate on the odds ratio of mortality remained significant for participants with BMI <18.5 kg/m² when the model was further adjusted for pretreatment serum hsCRP, ferritin, and albumin levels (OR 1.22, 95% CI: 1.01 to 1.48; 𝑃=0.04). When adjusted for concomitant tuberculosis treatment the odds ratio of mortality also remained significant for participants with BMI <18.5 kg/m² (OR 1.27, 95% CI: 1.06 to 1.51; 𝑃<0.01).