KCCQ-CSS (Kansas City Cardiomyopathy Questionnaire — Clinical Summary Score)

The Kansas City Cardiomyopathy Questionnaire is a survey people with heart failure fill out about their own lives: how short of breath they get, how much swelling they notice, whether they can climb stairs or carry groceries, how much the condition limits what they enjoy. The Clinical Summary Score condenses the symptom and physical-limitation answers into a single number from 0 to 100, where higher means less burden. It is a patient-reported outcome — the value comes from the patient, not from a scan or a blood draw.

That matters for GLP-1 research because heart failure with preserved ejection fraction is a condition where people feel terrible while many conventional measurements look unremarkable. A drug can only prove it helps if you ask the patient. So the KCCQ-CSS became a co-primary endpoint in STEP-HFpEF, the first trial to test a GLP-1 specifically in obesity-related HFpEF.

The result, published in the New England Journal of Medicine in 2023: among 529 participants with HFpEF and a BMI of 30 or higher, the mean KCCQ-CSS rose 16.6 points on semaglutide 2.4 mg and 8.7 points on placebo over 52 weeks — an estimated difference of 7.8 points in semaglutide’s favor. Six-minute walk distance improved by 20.3 meters more than placebo, and body weight fell 10.7 percentage points more. Our STEP-HFpEF deep dive unpacks the design.

Here is the common confusion. People see “7.8 points” and read it as the score patients reached. It is not. Both groups improved; 7.8 is the gap between them. Placebo groups in symptom trials routinely improve because of attention, structure and regression to the mean, and the honest question is always how much of the change the drug itself explains.

Worth asking your clinician: whether your heart-failure symptoms are being tracked with a structured tool at all, and whether obesity is being treated as part of the heart-failure plan rather than as a separate problem. Our roundup of GLP-1 cardiovascular studies and the SUMMIT trial page cover the tirzepatide counterpart.