Background <p>People with intellectual disabilities suffer from several chronic diseases earlier and more often. At the same time, they use medical screenings to prevent such diseases very irregularly due to a variety of barriers (e.g., social, communicative). Additionally, they often have to manage complex medication regimens characterised by polypharmacy and psychotropic drugs. This complexity often leads to low medication adherence. This study aimed to improve medication adherence and the uptake of medical screenings in adult clients with intellectual disabilities.</p> Methods <p>We conducted a randomised-controlled trial with waiting list and three months follow up in Germany. Clinical nurse specialists provided education to the clients and their caregivers about their medication and medical screenings during two home visits over a three-month period. They analysed the existing medication management and initiated changes where necessary. The control intervention was usual care. Inclusion criteria were: ICD diagnosis F70-79, ≥ 18 years, complex medication regimen (≥ 5 prescribed drugs) understanding of the German language. The primary outcome was medication adherence (MARS-D). Secondary outcomes were the use of medical screenings, complexity of the medication regimen, psychotropic medication, health-related quality of life and health status. Participants were randomised using block randomisation. Raters and analysts were blinded. Analysis was conducted via analysis of covariance (ANCOVA).</p> Results <p>We recruited 162 participants, of whom 154 could be analysed. In the intervention group adherence changed from 24.7 ± 1.1 to 24.9 ± 0.4 and in control group from 24.8 ± 0.9 to 25.0 ± 1.2. A significant difference between the study groups (<i>p</i> &gt; 0.05) was found only for the MRCI-D subscale “application forms” with a slightly lower complexity in the intervention group (η &lt; 0.06, <i>p</i> &lt; 0.05).</p> Conclusions <p>Based on quantitative evidence nurse-led home visits did not improve medication adherence. In addition, there were no clinically meaningful changes in the secondary outcomes. The study aimed to recruit people with intellectual disabilities from a range of settings, but the vast majority of participants lived in the residential care setting. This resulted in people having high adherence at baseline. Furthermore, the three-month interval between the two visits may have been too short.</p> Trial registration <p>German Clinical Trials Register DRKS00014101 (date registered: 17/08/2018).</p>