Prognostic Value of the CALLY Index in Patients With Sepsis (CALLY-SEP)

Prognostic Value of the CALLY Index in Intensive Care Patients Diagnosed With Sepsis: A Retrospective Cohort Study

This retrospective observational study evaluates the prognostic value of the C-reactive protein-albumin-lymphocyte (CALLY) index in adult patients with sepsis admitted to the intensive care unit (ICU). The CALLY index reflects inflammatory, nutritional, and immunologic status and may serve as a predictor of clinical outcomes.

CALLY Index values will be obtained on Day 0, Day 3, and Day 5 of ICU admission using routinely collected laboratory data. The primary objective is to determine the association between CALLY Index values and 30-day all-cause mortality. Secondary objectives include assessing the relationship between temporal CALLY changes and the development of acute kidney injury (AKI) within the first 7 days of ICU admission, as well as correlations between the Day-0 CALLY Index and established severity scores such as SOFA and APACHE II.

As this retrospective study uses existing electronic medical records, no additional procedures or interventions will be performed, and no added risk to patients is involved.

Study Overview

• Status: Completed
• Conditions: Sepsis

Detailed Description

Sepsis is a life-threatening condition characterized by a dysregulated host response to infection and is frequently associated with multiorgan dysfunction and high mortality. Early identification of patients at increased risk of poor outcomes remains a major challenge in critical care. The C-reactive protein-albumin-lymphocyte (CALLY) Index is a composite biomarker that reflects inflammatory, nutritional, and immune status. Although recent studies have explored the prognostic value of CALLY in critically ill populations, the significance of serial measurements and temporal changes in patients with sepsis has not been fully established.

This retrospective observational study will include adult patients diagnosed with sepsis according to Sepsis-3 criteria who were admitted to the intensive care unit (ICU) between January 2023 and December 2024. The CALLY Index will be calculated using the following formula:

Albumin (g/L) × lymphocyte count (10⁹/L) × 100 ÷ CRP (mg/L).

CALLY values will be obtained at predefined time points: Day 0 (within 2 hours of ICU admission), Day 3, and Day 5, extracted from the hospital's electronic medical record system.

The primary aim of the study is to evaluate the association between CALLY Index values and 30-day all-cause mortality. Secondary aims include assessing the relationship between temporal changes in CALLY (ΔCALLY₃-₀, ΔCALLY₅-₀, and linear trend slope) and the development of acute kidney injury (AKI) within the first 7 days of ICU admission, as well as examining correlations between the Day-0 CALLY Index and commonly used clinical severity scores, including SOFA and APACHE II.

All study data will be obtained retrospectively from the hospital's electronic records. No additional tests, procedures, or interventions will be performed. As the study utilizes existing clinical data without influencing patient management, it poses no additional risks to participants. The findings may support improved early risk stratification, monitoring of disease progression, and refinement of prognostic assessment in patients with sepsis.

• Study Type: Observational
• Enrollment (Actual): 276

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Ankara, Turkey (Türkiye), 06100
    • Ankara University Faculty of Medicine - Intensive Care Unit

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult ICU patients diagnosed with sepsis and treated at Ankara University Medical Faculty Hospital.

Description

Inclusion Criteria:

• Age ≥ 18 years

  • Sepsis diagnosis meeting Sepsis-3 criteria
  • ICU stay ≥ 5 days
  • Complete CRP, albumin, and lymphocyte laboratory results available for days 0, 3, and 5

Exclusion Criteria:

• • Chronic Kidney Disease stage ≥3

  • Liver diseases including cirrhosis, chronic hepatitis, or hepatic failure
  • Hematologic diseases such as leukemia, lymphoma, MDS, or multiple myeloma
  • Rheumatologic diseases including SLE, rheumatoid arthritis, or systemic sclerosis
  • Use of immunosuppressive therapy
  • ICU stay shorter than 5 days
  • COVID-19 positive status
  • Missing laboratory data preventing calculation of CALLY index

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Sepsis Cohort; Adult ICU patients diagnosed with sepsis according to Sepsis-3 criteria whose CALLY index values were obtained on day 0, day 3, and day 5.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
30-day All-Cause Mortality	Proportion of adult ICU patients with sepsis who die from any cause within 30 days after ICU admission. Vital status at 30 days will be obtained exclusively from the hospital electronic medical record system. Unit of measure: Percentage of participants. The CALLY Index will be calculated as: Albumin (g/L) × lymphocyte count (10⁹/L) × 100 ÷ CRP (mg/L). CALLY Index values measured on Day 0, Day 3, and Day 5 will be used as predictor variables in prognostic analyses, but they are not part of this outcome measure.	30 days after ICU admission

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Acute Kidney Injury (AKI) Development	Occurrence of acute kidney injury (AKI) during ICU admission, defined according to KDIGO criteria (increase in serum creatinine or decrease in urine output). Unit of measure: Number of participants with AKI. CALLY Index values and temporal CALLY changes (ΔCALLY_3-0 and ΔCALLY_5-0) will be analyzed as predictor variables, but they are not part of this outcome measure.	Up to 7 days after ICU admission
Correlation Between CALLY Index Trends and Clinical Outcomes (Mortality and AKI)	This outcome will assess the correlation between temporal changes in the CALLY Index and clinical outcomes (30-day mortality and AKI). CALLY Index will be calculated using the formula: Albumin (g/L) × lymphocyte count (10⁹/L) × 100 ÷ CRP (mg/L). Temporal CALLY changes will include: ΔCALLY₃-₀ (difference between Day-3 and Day-0 values),; ΔCALLY₅-₀ (difference between Day-5 and Day-0 values),; CALLY trend slope (calculated using linear regression across Day-0, Day-3, and Day-5 values). These variables will be used as predictor variables in prognostic analyses. Unit of measure: Correlation coefficient	Day 0 to Day 5 (first 5 ICU days)
Correlation Between Day-0 CALLY Index and Severity Scores (SOFA, APACHE II)	This outcome will assess the correlation coefficient between the Day-0 CALLY Index and severity scores (SOFA and APACHE II). The CALLY Index will be calculated as: Albumin (g/L) × lymphocyte count (10⁹/L) × 100 ÷ CRP (mg/L), using laboratory results obtained within 2 hours of ICU admission (Day 0). SOFA score will be measured using the standard Sequential Organ Failure Assessment scale (range: 0-24). APACHE II score will be calculated using the established APACHE II scoring system (range: 0-71). Unit of measure: Correlation coefficient	Day 0 (within 2 hours of ICU admission)

Collaborators and Investigators

• Sponsor: Ankara University

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2023
• Primary Completion (Actual): December 31, 2024
• Study Completion (Actual): January 1, 2025

Study Registration Dates

• First Submitted: November 21, 2025
• First Submitted That Met QC Criteria: December 2, 2025
• First Posted (Actual): December 16, 2025

Study Record Updates

• Last Update Posted (Actual): December 16, 2025
• Last Update Submitted That Met QC Criteria: December 2, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Intensive Care Unit; Sepsis; Mortality; Acute Kidney Injury; APACHE II; SOFA Score; CALLY Index
• Additional Relevant MeSH Terms: Urogenital Diseases; Pathologic Processes; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Infections; Systemic Inflammatory Response Syndrome; Inflammation; Renal Insufficiency; Pathological Conditions, Signs and Symptoms; Acute Kidney Injury; Sepsis
• Other Study ID Numbers: CALLY-Sepsis-2025-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No