Objective

Analysis of routinely collected electronic health data is a key tool for long-term condition research and practice for hospitalised patients. This requires accurate and complete ascertainment of a broad range of diagnoses, something not always recorded on an admission document at a single point in time. This study aimed to ascertain how far back in time electronic hospital records need to be interrogated to capture long-term condition diagnoses.

Setting

Adult acute hospital in England.

Design

Retrospective observational study of routinely collected hospital electronic health record data.

Participants

Participants whose first recorded admission for chronic obstructive pulmonary disease (COPD) exacerbation (n=560) or acute stroke (n=2142) between January and December 2018 and who had a minimum of 10 years of data prior to the index date.

Outcome

The study identified the most common International Classification of Diseases version 10-coded diagnoses received by patients with COPD and acute stroke separately. For each diagnosis, the study derived the number of patients with the diagnosis recorded at least once over the full 10-year lookback period, and then compared this with shorter lookback periods from 1 year to 9 years prior to the admission.

Methods

To understand why neutrophils (a type of white blood cell) don’t work properly in older adults with community-acquired pneumonia (CAP) and sepsis, researchers compared them to both older adults without these conditions and healthy young adults. They looked at how well the neutrophil’s function and how they produce energy from sugar in the blood.

Results

Seven of the top 10 most common diagnoses in the COPD dataset reached >90% completeness by 6 years of lookback. Atrial fibrillation and diabetes were >90% coded with 2–3 years of lookback, but hypertension and asthma completeness continued to rise all the way out to 10 years of lookback. For stroke, 4 of the top 10 reached 90% completeness by 5 years of lookback; angina pectoris was >90% coded at 7 years and previous transient ischaemic attack completeness continued to rise out to 10 years of lookback.

Conclusions

A 7-year lookback captures most, but not all, common diagnoses. Lookback duration should be tailored to the conditions being studied.