Comparison of Sequential Organ Failure Assessment (SOFA) Score and SOFA Score with pH in Outcome Prediction among ICU Patients: A Prospective Observational Study.

Arun  Kumar; Prashant  Kumar; Abhishek  Choudhury

doi:10.51168/sjhrafrica.v6i9.2177

Authors

Arun Kumar DrNB Resident, Department of Critical Care Medicine, Paras HMRI Hospital, Patna, Bihar, India
Prashant Kumar Consultant & Incharge ICU, Department of Critical Care Medicine, Paras HMRI Hospital, Patna, Bihar, India.
Abhishek Choudhury Senior Consultant Internal Medicine and Critical care, Department of Critical Care Medicine, Paras HMRI Hospital, Patna, Bihar, India.

DOI:

https://doi.org/10.51168/sjhrafrica.v6i9.2177

Keywords:

SOFA score, Arterial pH, Outcome prediction, Critical care

Abstract

Background:

The SOFA score is commonly employed in ICUs to assess disease severity and forecast patient outcomes. Nevertheless, it does not include all physiologic variables that may influence prognosis. Arterial blood pH, a reflection of global metabolic and respiratory balance, could provide added predictive value.

Objective:

To determine whether combining arterial pH with the SOFA score improves the prediction of in-hospital mortality in ICU patients.

Methods:

Between July 2024 and June 2025, this prospective observational study was carried out at the intensive care unit of Paras HMRI Hospital in Patna. In the first 24 hours, we enrolled 275 consecutive adults who had arterial blood gas analysis and full SOFA data. Two models were compared: SOFA alone and SOFA plus pH. Model performance was evaluated by clinical utility, calibration, and discrimination.

Results:

In-hospital mortality occurred in 24.0% (66/275) of patients. The AUC for SOFA + pH was 0.82 (95% CI 0.77–0.87), a statistically significant improvement (p=0.030) compared to 0.78 (95% CI 0.72–0.83) for SOFA alone. Calibration metrics were more favourable with SOFA + pH (slope 1.02 vs 0.94). The Brier score also improved (0.138 vs 0.145). Decision curve analysis demonstrated superior net benefit for SOFA + pH at threshold probabilities between 10–40%.

Conclusion:

Incorporating arterial pH into SOFA enhances the accuracy of mortality prediction. This adjustment requires no additional cost or technology and may support better risk stratification in daily ICU practice.

Recommendations:
Integrating arterial pH into routine SOFA scoring is recommended for early risk stratification and improved mortality prediction among ICU patients. This approach can be easily adopted in all critical care units without additional cost

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