A Care Concept of Community Health Nursing Interventions for Adults With Chronic Health Conditions in an Urban Area: Protocol for a Randomized Controlled Field Trial (CoSta Study)
Authors: Nock Annike Morgane , Iversen Linda , Waidhas Lukas , Zapf Antonia , Seifert Caroline , Petersen-Ewert Corinna 
Published: July 2022

Background
Implementing community health nursing programs is a new field of application in the primary health sector of Germany. Hence, there is limited evidence of effective community-based and nurse-led interventions with regard to the German health care system. International research findings are mostly not transferable. The Community Health Nursing in der Stadt (CoSta; ie, “Community Health Nursing in the City”) project is the first study that examines a community health nurse–led intervention for adults with chronic health conditions.

Objective
This study protocol describes the design and methods of a randomized controlled field trial that will investigate if a community health nurse–based intervention has an impact on health-related quality of life in adults with chronic conditions.

Methods
The study was designed as a randomized controlled trial that will be conducted under real-life conditions in the field. In a 4-month period, patients with at least 1 chronic International Classification of Diseases, Tenth Revision, diagnosis will be enrolled. Participants will be randomly allocated to an intervention group or a control group. The sample size was assumed based on an effect size of 0.50 with a significance level of .05, using a 2-sided (2-tailed), 2-sample unequal variance t test. The control group will be treated as usual. The intervention group will receive—in addition to the usual treatment—preventive home visits; consultations; and educative training, which will be offered by 2 community health nurses for up to 12 months. Both groups will be followed up at baseline, after 6 months, and after 12 months. The primary outcome measure is the mental component summary score from the 36-Item Short Form Health Survey after 12-months. Secondary patient outcomes will be included. The study received ethics approval from the Competence Health Center’s institutional review board at the University of Applied Sciences Hamburg (procedure number: 2020-14).

Results
The CoSta project was funded by the Federal Ministry of Education and Research Germany (contract number: 13FH019SX8). In total, 187 participants were recruited at the beginning of August 2021. Further, 92 were excluded and 94 were randomized. Data collection will be conducted until the end of 2022.

Conclusions
Our study will provide data with regard to the effectiveness of community nurse–led interventions that focus on the treatment of vulnerable adults with chronic health conditions in a community health center. In secondary analyses, the associations among influencing social factors (education, income, and employment) will be examined. We expect results that will help reduce the research-to-practice gap.

Trial Registration
German Clinical Trials Register DRKS00026164; https://tinyurl.com/yckxc5ut

International Registered Report Identifier (IRRID)
DERR1-10.2196/37965