Ear infections, or "otitis media," can cause of a lot of pain and discomfort in youngsters. In some children, persistent infections result in hearing loss. But what sort of treatment should these children have, and how can doctors work out what is actually effective?

Let us take a look at the "OSTRICH" clinical trial, which investigated the impact of a short course of oral steroids (prednisolone) in children with persistent ear infection leading to a fluid build-up in the ear, and hearing loss.

What is a clinical trial?

Clinical trials are the favored type of study for showing cause and effect. They sit near the top of the study pecking order, only outdone in importance by summaries of lots of clinical trials put together.

Clinical trials can assess the impact of a medication on a disease or condition. Researchers generally test a particular treatment and compare the outcome to a different treatment or no treatment (if it's ethical to do so).

The ideal design is one when the researchers and participants do not know who is assigned to the different treatments being tested. This is referred to as blinding.

Blinding may not always be possible. In food trials for example (where we do most of our work), it is very hard to blind a participant from the food they need to eat. Measures can be taken to minimize the impact of this, though.

The OSTRICH trial

The OSTRICH trial used an approach where they tested a real medication, in this case, a steroid, and compared it to a treatment that was almost the same but without the active ingredient called a placebo.

The researchers worked with 389 children aged two to eight years with ear infection symptoms, the fluid buildup for at least three months, and with confirmed hearing loss in both ears. Two hundred kids were allocated to received oral steroids, and 189 to receive placebo for seven days.

With this approach, they recorded the impact of the treatments on the ear canal and middle ear, and also conducted clinical tests for hearing. The parents kept a diary of symptoms and completed questionnaires.

The children were followed up five weeks, six months and 12 months after completion of the treatment. The primary outcome for the trial was fair hearing confirmed by an audiometry test at five weeks.

Both the families and the researchers did not know who had the real medication until the study was finished – this is called double blinding. This period meant that researchers had to be careful with the information they collected to avoid potential errors.

Kids are unpredictable

Even with the best-laid plans, children are hard to predict. As well as looking at the effect of a medication on a disease, the number of study participants who follow all instructions and finish the study as per the plan is an important outcome.