function calculateMortalityRate() {
// Get input values
var totalAdmissions = document.getElementById('totalAdmissions').value;
var deaths = document.getElementById('deaths30Days').value;
var resultBox = document.getElementById('resultBox');
var finalRateDisplay = document.getElementById('finalRate');
var interpretationText = document.getElementById('interpretationText');
var errorMsg = document.getElementById('errorMessage');
// Reset display
resultBox.style.display = 'none';
errorMsg.style.display = 'none';
errorMsg.innerHTML = ";
// Validation logic
if (totalAdmissions === "" || deaths === "") {
errorMsg.innerHTML = "Please enter values for both fields.";
errorMsg.style.display = 'block';
return;
}
var total = parseFloat(totalAdmissions);
var dead = parseFloat(deaths);
if (isNaN(total) || isNaN(dead)) {
errorMsg.innerHTML = "Please enter valid numeric values.";
errorMsg.style.display = 'block';
return;
}
if (total <= 0) {
errorMsg.innerHTML = "Total admissions must be greater than zero.";
errorMsg.style.display = 'block';
return;
}
if (dead total) {
errorMsg.innerHTML = "Number of deaths cannot exceed the total number of patients.";
errorMsg.style.display = 'block';
return;
}
// Calculation
var mortalityRate = (dead / total) * 100;
var roundedRate = mortalityRate.toFixed(2);
// Update DOM
finalRateDisplay.innerHTML = roundedRate + "%";
// Dynamic interpretation
var interpretation = "Out of " + total.toLocaleString() + " patients, " + dead.toLocaleString() + " passed away within the 30-day window.";
interpretationText.innerHTML = interpretation;
resultBox.style.display = 'block';
}
How to Calculate 30-Day Mortality Rate
The 30-day mortality rate is a critical key performance indicator (KPI) in healthcare epidemiology and hospital administration. It measures the percentage of patients who die within 30 days of being admitted to a hospital or undergoing a specific medical procedure, such as surgery or treatment for heart failure.
This metric is widely used by health organizations and regulatory bodies to assess the quality of care, surgical safety, and overall hospital performance. It includes deaths that occur both within the hospital and after discharge, provided they fall within the 30-day window from the index admission date.
The Calculation Formula
Calculating the unadjusted 30-day mortality rate involves a straightforward ratio converted into a percentage. The formula focuses on the relationship between total cases and adverse outcomes (deaths).
Mortality Rate (%) = (Deaths within 30 Days / Total Admissions) × 100
Where:
Total Admissions: The total number of patients included in the cohort (e.g., all patients undergoing heart bypass surgery in 2023).
Deaths within 30 Days: The count of patients from that specific cohort who died from any cause within 30 days of their admission or procedure date.
Example Calculation
Let's assume a hospital performs 500 hip replacement surgeries in a single year. Post-operative data tracking reveals that 15 of these patients passed away within 30 days of the surgery.
To calculate the rate:
Divide deaths by total patients: 15 / 500 = 0.03
Multiply by 100 to get the percentage: 0.03 × 100 = 3.0%
In this scenario, the 30-day mortality rate for hip replacements at this facility is 3.0%.
Why is this Metric Important?
The 30-day mortality rate serves several vital functions in the healthcare ecosystem:
Quality Benchmarking: It allows hospitals to compare their performance against national averages or peer institutions.
Patient Safety: High mortality rates can trigger internal audits to identify systemic issues, such as infection control problems or surgical errors.
Accountability: Publicly reporting these rates helps patients make informed decisions about where to seek care.
Limitations and Risk Adjustment
The calculator above provides the crude or unadjusted mortality rate. However, in professional medical statistics, rates are often "risk-adjusted." This means statisticians apply mathematical models to account for the fact that some hospitals treat sicker patients (older, more comorbidities) than others.
An unadjusted rate might unfairly penalize a hospital that specializes in high-risk trauma cases. Therefore, while the crude calculation is essential for internal tracking, comparisons between hospitals should ideally use risk-adjusted data.