How can we improve the evidence base for monitoring long term conditions in primary care?

Problem

Patients with long term conditions (LTC), such as chronic kidney disease (CKD), type 2 diabetes mellitus (T2DM), and hypertension, have regular blood tests to monitor disease progression, response to treatment, and detection of complications. There is currently no robust evidence to inform recommendations on monitoring and most guidance is largely based on expert opinion. Creating this evidence base is challenging because the benefits and harms of testing are dependent on what is done in response to the test result. The aim of this project is to develop evidence-based testing panels to monitor people with CKD, T2DM, or hypertension.

Approach

We created a list of candidate tests to consider for our panels by identifying tests that are currently recommended and tests that are currently done in these patient populations (using routine data). We defined a series of filtering questions to determine whether there was evidence to support the rational of monitoring, such as ‘is this patient population at increased risk of the condition the test tries to pick up’ and ‘can the GP do anything in response to an abnormal test result?’. Through a series of rapid reviews we identified evidence to answer each question. The evidence was presented at a consensus meeting where clinicians and patients voted for inclusion or exclusion of each test or whether further evidence was needed. We are currently performing further analyses using routinely collected primary care data to collect additional evidence.

Findings

We found sufficient evidence to include HbA1c and eGFR for monitoring T2DM patients; haemoglobin and eGFR for CKD; and eGFR for hypertension. The consensus panel excluded the following tests: haematinics, because they are not necessary to detect anaemia in addition to measuring haemoglobin levels; clotting tests, because there is no rationale linking bleeding disorders to the LTCs of interest; B-type natriuretic peptide, because it has a low accuracy for heart failure; and liver function tests for the purpose of drug monitoring, because it can be tested once after starting a new drug and there is no need for regular monitoring afterwards. However, the majority of tests were selected for further analyses, including blood electrolytes, lipid profile, full blood count, and bone profile, which are still ongoing.

Consequences

The cost-effectiveness of the evidence-based testing panels need to be tested in clinical practice. We are currently developing an intervention package and are planning to run a feasibility trial. This programme of work has the potential to change how LTCs are monitored in primary care, ultimately improving patient outcomes, and leading to more efficient use of healthcare resources.