Practice exercise (made-up values, not clinical guidance). A town has 12 000 inhabitants. At the start of a year, 250 of them have a chronic disease. During the year, 47 more people are newly diagnosed (assume nobody moves away or dies). Find the point prevalence P at the start of the year per 1000 inhabitants. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). A new test was compared with the reference standard in a study (see the 2 × 2 table). Find the prevalence in the study p as a percentage. Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). In a randomised trial, 540 patients received a new treatment and 390 received the control treatment. The table shows how many in each group had a side effect. Find the number needed to harm NNH: how many patients must be treated for one extra patient to have the side effect? Round up to a whole number of patients.
Practice exercise (made-up values, not clinical guidance). A case-control study compares 140 patients with a disease (cases) and 410 people without it (controls). The table shows how many in each group were exposed to a risk factor. Find the odds ratio OR for the exposure. Round to two decimal places.
Practice exercise (made-up values, not clinical guidance). 10 000 people are screened with a test of sensitivity 70% and specificity 99%. The prevalence of the disease is 12%. How many true-positive results TP are expected?
Practice exercise (made-up values, not clinical guidance). Without a drug, 12% of patients have a certain side effect during a year. The drug raises this risk with a relative risk of RR = 1.61. Find the number needed to harm NNH: how many patients must take the drug for a year for one extra patient to have the side effect? Round up to a whole number of patients.
Full step-by-step solutions: practise this topic on examproblems.com.