Does multimorbidity predict the number of patient contacts: a matter of definition

Johannes Hauswaldt, Katharina Schmalstieg, Wolfgang Himmel

Keywords: multimorbidity; chronic condition; electronic medical record; practice visits; family practice; patient care management

Care for multimorbid patients is a characteristic feature in general practice. Earlier studies report a strong impact of multimorbidity on number of patient contacts, taken as an indicator of a GP’s workload. This association may be overestimated, due to an inflated definition of multimorbidity and lack of a time delimiter in definition.

Research questions:
Which impact does multimorbidity have on the number of patient contacts?
How much changes this association with the definition of multimorbidity?

The analysis is based on electronic medical records (EMR) of 236,038 patients from 142 practices over 14 years.
We investigated the association between a patient´s annual number of contacts and four definitions of multimorbidity, ranging from a simple definition (‘two diseases’) to an advanced definition (‘at least three chronic conditions’). A time delimiter for multimorbidity was included and combined with operationalising the concept of ‘chronic condition‘, allowing for patients to change annually between being a multimorbid patient and a non-multimorbid status. Mixed-effects multiple regression analyses were performed with patient contacts as criterion and four definitions of multimorbidity as separate predictors, controlling for patient and practice characteristics, with beta-coefficients and z-values as measures of effect.

Annual percentage of multimorbid patients in general practice ranged between 74% (simple model) and 13% (advanced model). Multimorbidity had impact on patients’ annual number of contacts, but similar predictors were patient's age and a practice‘s average annual number of contacts. Differences in impact between the four models of multimorbidity were small.

Multimorbidity seems to be less prevalent in primary care practices than usually is estimated, if a temporal delimiter is considered and advanced definitions of multimorbidity are applied. Multimorbidity influences a patient’s number of contacts and, thus, a GP’s workload. Practice characteristics, such as its appointment scheduling, have a similar impact on contact frequency as patient’s age or multimorbidity.

Points for discussion:
Which definition of multimorbidity do you prefer, and for what reason?

Strength and weaknesses of applying multimorbidity concepts in PHC?

How can we focus on ‚morbidity burden‘ rather than on counting diagnoses in order to detect complex patients in primary care?