Using anonymised information from electronic health records is an efficient and low-cost way of following up subjects years after the treatment phase of a study completes
Typically, randomised control trials are relatively short term, and due to costs and available resources, there is limited opportunity for them to be re-visited or extended. That means the effects of treatments cannot be scrutinised beyond the duration of the study, typically 1-2 years.
But with the advent of electronic health records and with consent of the subjects, data analysts can match patients to their medical records and access data quickly. As a result, the cost of follow-up, using data collected during routine healthcare, is potentially relatively small and does not increase with the number of participants.
Researchers Swansea University Medical School used routinely-collected electronic health data stored in the Secure Anonymised Information Linkage (SAIL) database at the university, to revisit a trial investigating the impact of probiotics taken during pregnancy on the incidence of childhood asthma and eczema in a group of children at six months and then two years of age.
The study, ‘Long term extension of a randomised controlled trial of probiotics using electronic health records’, was published last week in Scientific Reports.
In all, 435 of 452 (96 percent) of the participants in the trial were located in the SAIL database. The records were assessed as being suitable to allow meaningful follow-up for 422 participants at two years, (which was within the time frame of the original trial), and 370 participants at five years.
The study also introduced a further level of linkage: pregnant women were recruited to the trial, but follow-up was extended to the more relevant population of their children, who were identified through electronic health records.
The findings demonstrate the potential of using anonymised, routinely collected, electronic health records, such as those linked in SAIL, for more complete trial results. Results showed that SAIL can help track trial participants, with long term monitoring of medical interventions and health outcomes, and providing new insights into population health.
“In this study we reported on the feasibility and efficiency of electronic follow up, and compared it with traditional trial follow up,” said Sue Jordan of Swansea University’s College of Human and Health Science, who led the study. “We gained new insights from outcomes electronically recorded three years after the end of the trial, and could then identify the differences between trial data and electronic data.”
The SAIL database started to collect records from primary care and other public services ten years ago. It now gives researchers secure remote access to billions of anonymised person-based population, health and social care data records. SAIL makes person-based population data available for genuine research purposes only.
The use of electronic databases in clinical trials has been hailed as one of the major benefits of having a nationwide electronic health records system. But said Jordan, “Few studies have demonstrated this benefit, or formally assessed the relationship between traditional trial data and electronic health records databases.”
Amongst the key findings the research shows that:
- Using SAIL, the retention of children from lower socio-economic groups was improved, which helped reduce volunteer bias
- Results from the electronic follow up were more reliable due to reduced risk of bias, unreliability or inaccuracy in participants’ recall
- New insights were gained from the electronic five year follow up, particularly for asthma, which typically appears after two years of age
- For the electronic follow up at five years, retention was still high and free of bias in socio-economic status
- Any future extension of trial follow-up would be straightforward.
Follow-up of trial participants on anonymised routine electronic health care databases such as SAIL offers great potential to maximise the economic efficiency of trials and allow access to a fuller range of health information.
Michael Gravenor, who led the data analysis for the study said, “These results lead us to conclude that using electronic health records has benefits relating to the cost-effective, long term monitoring of complex interventions, which could have a positive impact for future clinical trial design.”