Date of Approval:
Blood tests are used to help doctors identify and diagnose illnesses. Doctors often perform blood tests during routine health check-ups. To diagnose diabetes, for example, blood glucose (sugar) levels in blood are measured. If they exceed a certain predefined limit, the patient may have diabetes. Standard reference values are the basis for the interpretation of test results. However, lab values are subject to complex control mechanisms within the body and can differ by individual, despite known normal values. Thus, it is not clear whether the "one size fits all" approach is always appropriate. Age, sex and underlying diseases, for example, can have an influence on test results. Information on normal ranges or reference values in specific patient subgroups is often not available or is based on studies with small sample sizes. As doctors perform and record many blood tests during routine health check-ups, the CPRD GOLD provides an ideal setting to assess and describe subgroup-specific blood tests and the recorded range of lab values. This will provide an overview of the distribution of lab values in middle-aged persons in a real-world primary care setting.
Most routine lab diagnostics were developed to detect a specific disease, but now are often performed during routine health checks or in patients with ill-defined symptoms. The interpretation of these test results poses a challenge in patient care, as normal values and acceptable deviations from the norm are not well defined or understood. We plan to study all CPRD GOLD patients aged 40-79 years present in the data between January 1, 2004 and December 31, 2017 to describe the utilization of major routine blood tests such as lipid and glucose levels, liver or thyroid function tests and blood cell counts. Using descriptive statistics such as mean and standard deviation, range and percentiles, we will quantify the frequency of testing per year during the study period and describe the distribution of measured lab values for the different lab tests parameters in this middle-aged adult primary care population. We will provide this information for the whole study population, as well as for subgroups stratified by age, sex and prevalent underlying metabolic or cardiovascular diseases.
Health Outcomes to be Measured:
Frequency of and recorded results per person and per year of the major routinely performed diagnostic blood tests (see definition below in section N)
Susan Jick - Chief Investigator - BCDSP - Boston Collaborative Drug Surveillance Program
Cornelia Schneider - Corresponding Applicant - University of Basel
Christoph Meier - Collaborator - University of Basel