Prospective single-arm cohort study

A prospective single-arm cohort study is a type of observational clinical study with the following characteristics:

✅ Definition:

A prospective single-arm cohort study follows a group of participants over time without a comparison (control) group, where all participants receive the same treatment or intervention, and outcomes are measured forward in time from the point of enrollment.

🧠 Key Components:

Prospective: Data is collected forward from a defined starting point (e.g., initiation of treatment).

Single-arm: There is only one group in the study; no randomization or control/placebo group.

Cohort: A defined group of individuals with shared characteristics (e.g., disease, treatment) is followed over time.

Study purpose: Often used to assess feasibility, safety, or efficacy of an intervention in early-phase clinical research.

📘 Example Use Case:

Evaluating the safety and outcomes of a new surgical technique in 100 patients with Chiari I malformation, all treated the same way and followed for 12 months ¹⁾

⚠️ Limitations:

No control group limits ability to attribute causality.

Susceptible to bias (e.g., selection bias, confounding).

Results are hypothesis-generating, not confirmatory.