Adequacy of Prostate-Specific Antigen (PSA) Requests

Sample size and recruitment procedure: During the last semester of 2016, 9,963 PSA determinations were carried out at Sant Joan d'Alacant Hospital and a similar number at Alicante General Hospital. Primary health centres requested most determinations. The prevalence of prostate cancer in 2012 was 527.3/100,000 men in Spain. Considering that there are about 120,000 men in each of the included Departments of Health, approximately 630 men will have the diagnosis of prostate cancer in each of them. According to the established recommendations, a patient with prostate cancer had a PSA determination every 3-6 months. Consequently, 1,260 determinations per centre would correspond to prostate cancer patients each 6 months. Therefore, the investigators would have in each department approximately 8,740 determinations of patients without prostate cancer, and therefore, possible candidates to enter in our study. According to a pilot study with 360 patients in which 35.6% of the requested PSA determinations do not follow the available recommendations with a 95% margin of error and 2% accuracy, the investigators will include a total of 1,410 determinations from the two centres. Hence, for the determination of specific objective 1, the investigators will select a random sample of 705 patients with a PSA determination in each centre. From each clinical analysis laboratory, the investigators will randomly select 300 primary care analyses with PSA determination for each month from January to April 2018. The investigators will select the patients who satisfy the inclusion criteria consecutively from this list until 180 are included. Data collection procedure: The investigators will collect the following variables from the medical records for each patient: Demographic characteristics, setting (primary care or clinical service), PSA tests carried out in the last 12 months and PSA value, anthropometric measures and other comorbidities. The investigators will analyze the appropriateness of PSA determinations according to the criteria established by the clinical practice guidelines of the EAU, and the May 2018 update of the USPSTF. All the reviewers are trained in the use of these guidelines. A pilot study of a sample of 30 determinations will be independently evaluated by the nine researchers the application of the determined criteria. If the agreement is high, the rest of the determinations will be evaluated separately by at least two researchers using a predesigned google form. In case of disagreement between two of the evaluators, the case will review by a third, or discussed in a joint meeting with the rest of the team. Data analysis plan: The analysis will be performed using the Stata IC 15 program. The investigators will estimate the frequency and 95% confidence interval of the adequacy of PSA determinations to established recommendations. The investigators will evaluate the inter-observer agreement in the determination of adequacy using the Kappa index. In order to assess the relationship with potential explanatory variables, and the magnitude of the association, the investigators will calculate prevalence ratios. If necessary, a log-binomial regression will be performed to get an adjusted analysis.