Inter-contact intervals for temporal discrimination of acute from chronic care in general practice

Johannes Hauswaldt, Eva Hummers, Wolfgang Himmel

Keywords: Continuity of care, acute care, chronic condition, multimorbidity, frequent attendance

Background:

Continuity of care, a core value in longitudinal primary medical care, encloses episodes of acute care. For operationalization we suggested the inter-contact interval (ICI), that is the number of days between 2 consecutive contacts of a patient to general practice, as a basic measure.

Research questions:

Can ICI from real-world data be related to diagnoses and reason for contact, as an ICI use case application to discriminate acute from chronic care?

Method:

ICI were extracted from electronic medical record data of 155 German practices over 14 years, ICI of less than 8 days we categorized as suggesting “frequent attendance”. For understanding a patient’s temporal ICI changes, we performed ordinal time series analysis of m prior ICI for every ICI, with order m ranging from 1 to 20. ICD-codes, their frequencies, and patient’s chronic and multimorbid condition over time were associated with ICI, using logistic regression modelling (accepted error probability < .05).

Results:

We observed 6,698,739 ICI in 325,080 patients, with 44.7% “frequent attendance”. 1,345 ICD-code entities were found in 1,189,203 patients’ annual quarters.
Highest values of maximum likelihood in 675 significant ICD-code entities were reached from observation of 3 prior ICI (median, inter-quartile range 2 to 4). Diagnoses of the circulatory system, of the respiratory system and of endocrine-metabolic diseases required 2 (IQR 2 to 3) prior ICI to identify acute care, of the musculoskeletal system 3 (3 to 4), signs and symptoms not elsewhere classified 3 (2 to 4), and diseases of the digestive system 7 (1 to 18) prior ICI for acute care identification.

Conclusions:

The inter-contact interval is a simple and universal measure in primary medical care. Combined with operationalization of chronic and multimorbid condition, it allows for identification of patient’s frequent attendance and need for acute care, and contributes to comparable research into patient features.

Points for discussion:

Which features in a patient’s chronic or acute care benefit from using inter-contact intervals for research?

Do you know other ways to operationalize a patient’s frequent attendance or acute care episodes?

Is patient's chronic multimorbidity, that is at least 2 chronic conditions observed in 2 of 4 consecutive annual quarters, a useful measure in primary care research?

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