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Neutrophil-to-Lymphocyte Ratio and Mean Platelet Volume in Relation to Pressure Ulcer Stages in a Palliative Care Unit: A Retrospective Single-Center Study

This retrospective study of non-oncological palliative inpatients found that admission neutrophil-to-lymphocyte ratio and mean platelet volume were not independently associated with pressure ulcer presence or stage, a null result attributed to the confounding effect of pre-existing chronic wounds in a referral-based setting and highlighting clinical risk scores as the primary actionable correlates.

Original authors: Mustafa Gökhan Bayram, Dinçer Fırat Şeker

Published 2026-07-03

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Mustafa Gökhan Bayram, Dinçer Fırat Şeker

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine a hospital ward as a busy train station. Patients arrive from all over, some with fresh injuries and others carrying wounds they've had for a long time. The researchers in this study wanted to see if they could use two simple, cheap blood tests—like checking the weather report for the body's internal inflammation—to predict how bad a patient's pressure sores (bedsores) were.

Here is the story of what they found, told simply:

The Two "Thermometers"

The researchers were looking at two specific numbers from a standard blood test:

NLR (Neutrophil-to-Lymphocyte Ratio): Think of this as a tug-of-war score between two types of immune cells. One fights infection, the other regulates the system. A high score usually means the body is in a state of high alert or inflammation.
MPV (Mean Platelet Volume): Imagine platelets as the body's "emergency repair crew." MPV measures the size of these workers. Bigger workers often mean the body is trying harder to fix something.

The big question was: If a patient has a deep, nasty sore (Stage III or IV), will these numbers be higher than if they have a shallow, red spot (Stage I or II)?

The Problem: The "Arrival" Confusion

The study took place in a palliative care unit (a place for people with serious, long-term illnesses who need comfort care). This is where the plot twist happens.

In this specific unit, almost all the patients with deep, severe sores had arrived there with those sores already on their bodies. They brought them from nursing homes or other hospitals.

The Deep Sores: 94% to 100% of the severe wounds were already there when the patient walked (or was wheeled) in.
The Shallow Sores: Most of the mild, early-stage sores were actually new and happened while the patient was in the hospital.

The Analogy:
Imagine you walk into a house and see a burnt kitchen. You want to know if the fire alarm (the blood test) is ringing because of this fire. But the fire started three days ago in a different house, and you just arrived. The smoke detector in your pocket isn't measuring the current fire in the kitchen; it's measuring the smoke from the fire that happened days ago, or the general smog in the city.

Because the severe wounds were "old news" by the time the patients arrived, the blood tests reflected the patients' overall health history (how sick they were before they came) rather than the specific stage of the wound they had when they arrived.

The Results: A Dead End for the Blood Tests

Because of the "arrival confusion" described above, the researchers couldn't find a clear link between the blood tests and the wound stages.

The Finding: The "thermometers" (NLR and MPV) didn't get hotter or bigger as the sores got deeper. A patient with a tiny red spot had similar blood numbers to a patient with a deep, open wound.
The Verdict: The study didn't prove that these blood tests don't work; it just proved that this specific study design couldn't tell if they work. It's like trying to measure the speed of a car by looking at a photo taken after the car has already stopped. The data was "inconclusive," not "negative."

What Did They Find? (The Real Clues)

While the blood tests were a dead end, the researchers found that clinical checklists were much better at predicting who had sores.

The Braden Score: This is a checklist doctors use to see how likely someone is to get bedsores (checking things like mobility, moisture, and sensation). A lower score (meaning the patient is less mobile and more at risk) strongly predicted the presence of sores.
The Karnofsky Score: This measures how well a patient can function in daily life. A lower score (meaning the patient is very dependent on others) also predicted sores.
Stroke: Patients who had a stroke were more likely to have sores, likely because strokes often lead to immobility.

The Big Picture

High Prevalence: About 40% of the patients in this unit had sores. This is a very high number, but it makes sense because these patients were extremely frail, mostly elderly, and had severe neurological issues (like dementia or stroke) rather than cancer.
The Lesson for Future Studies: The authors realized that in palliative care units, you can't just take a blood test when a patient arrives and compare it to their wound stage. The "old wounds" mess up the data. To truly know if blood tests predict wound severity, future studies would need to follow patients from the exact moment a new wound appears, which is very hard to do in a referral-based unit.

In short: The researchers tried to use blood tests to grade bedsores, but the patients arrived with "old" wounds that confused the results. Instead, they confirmed that simple physical checklists (Braden and Karnofsky scores) are the best tools we have right now to spot who is at risk.

Technical Summary: Neutrophil-to-Lymphocyte Ratio and Mean Platelet Volume in Relation to Pressure Ulcer Stages in a Palliative Care Unit

Problem Statement
Pressure ulcers (PUs) represent a significant source of morbidity in palliative care, particularly among non-oncological populations where epidemiology remains poorly described. While the neutrophil-to-lymphocyte ratio (NLR) and mean platelet volume (MPV) are established, low-cost markers of systemic inflammation used to assess PU development in intensive care, their utility in staging PUs within non-oncological palliative cohorts is unestablished. A critical gap exists in understanding whether these admission hematological markers correlate with the severity (stage) of existing ulcers or predict their presence in patients with advanced end-stage disease, profound immobility, and functional impairment.

Methodology
This was a retrospective, single-center study conducted at Zonguldak Atatürk State Hospital between January 1, 2022, and January 1, 2025. The study adhered to STROBE guidelines and the Declaration of Helsinki.

Cohort: From 348 screened admissions, 99 patients with active malignancy were excluded to eliminate hematological confounding (e.g., lymphopenia, myelosuppression) intrinsic to cancer and its treatment. The final analytic cohort consisted of 249 non-oncological palliative inpatients.
Data Collection: Admission complete blood counts were used to calculate NLR, MPV, platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII). Clinical variables included age, sex, length of stay, comorbidities, Karnofsky Performance Status (KPS), and Braden Risk Assessment Scale scores.
PU Assessment: PUs were staged by the attending physician using EPUAP/NPIAP criteria (Stages I–IV). Wounds were classified as "present on admission" or "hospital-acquired."
Statistical Analysis: The primary analysis examined the relationship between NLR/MPV and PU stage using the Kruskal–Wallis test and Spearman correlation. Secondary analyses utilized multivariable logistic regression to identify factors associated with PU presence and Cox proportional hazards models for time-to-event analysis of hospital-acquired PUs. No a priori power calculation was performed; post-hoc analysis indicated 80% power to detect a Spearman correlation of $|r| \ge 0.28$ .

Key Results

Prevalence and Epidemiology: The point prevalence of PUs was 40.2% (100/249). Among staged ulcers, the distribution was Stage I (19.0%), Stage II (61.0%), Stage III (17.0%), and Stage IV (3.0%). Notably, 94.1% of Stage III and 100% of Stage IV wounds were present on admission, whereas 94.7% of Stage I and 70.5% of Stage II wounds were hospital-acquired.
Marker-Stage Relationship (Primary Analysis): Neither NLR nor MPV differed significantly across PU stages (Kruskal–Wallis $p=0.521$ for NLR; $p=0.878$ for MPV). Spearman correlations were negligible and non-significant ( $r = -0.109$ for NLR; $r = -0.068$ for MPV). The markers failed to discriminate deep (Stages III–IV) from superficial (Stages I–II) wounds (AUC 0.43 for NLR; 0.44 for MPV).
Factors Associated with PU Presence (Secondary Analysis): In multivariable logistic regression, lower Braden scores (OR 0.677), lower KPS (OR 0.960), and longer length of stay (OR 1.045) were independently associated with PU presence. After adjustment, neither NLR nor MPV was independently associated with PU presence ( $p=0.48$ and $p=0.14$ , respectively).
Mortality: 30-day mortality was 14.1% and was associated with older age and lower functional status, but not with PU presence, NLR, or MPV.

Significance and Claims
The paper explicitly frames its findings with caution, arguing that the primary result (no association between markers and stage) should be interpreted as inconclusive rather than evidence of a null association. The authors identify a fundamental methodological limitation: in referral-based palliative units, advanced-stage ulcers are almost exclusively pre-existing. Consequently, admission NLR and MPV reflect the cumulative pre-referral systemic burden (chronic infection, malnutrition, immobility) rather than the inflammatory response to the specific wound stage. This "wound-origin/stage confound" renders cross-sectional admission-marker studies uninterpretable for determining marker-staging relationships in this setting.

The study's primary contributions are:

Epidemiological Characterization: Providing data on PU prevalence (40.2%) in a non-oncological palliative population, distinguishing between prevalent (admission) and incident (hospital-acquired) wounds.
Methodological Insight: Highlighting that the structural nature of referral-based palliative care (receiving patients with pre-existing chronic wounds) prevents the use of admission biomarkers to assess wound severity retrospectively.
Clinical Correlates: Confirming that clinical risk measures (Braden and Karnofsky scores) and stroke history are actionable correlates for PU presence, whereas inflammatory markers (NLR, MPV) did not show independent utility after adjustment.

The authors conclude that whether NLR or MPV track PU severity remains an open question that can only be resolved by prospective studies restricted to hospital-acquired ulcers, with markers measured at wound onset and adequate enrollment of deep-stage wounds.