A 2014 systematic review by Tessa van Loenen and her team investigated which characteristics of primary care organization influence avoidable hospitalization for chronic Ambulatory Care Sensitive Conditions.

Organizational aspects of primary care related to avoidable hospitalization: a systematic review.
van Loenen T, van den Berg MJ, Westert GP, Faber MJ
https://academic.oup.com/fampra/article/31/5/502/539081

The conclusion? Access to primary care and long term relationships.

Available evidence suggests that strong primary care in terms of adequate primary care physician supply and long-term relationships between primary care physicians and patients reduces hospitalizations for chronic ACSCs. There is a lack of evidence for the positive effects of many other organizational primary care aspects, such as specific disease management programs.

Another study by the same team looked at ‘The impact of primary care organization on avoidable hospital admissions for diabetes in 23 countries’.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4911022/

Again, the review showed that continuity of care is associated with lower rates of diabetes-related hospitalisations.

Other aspects of primary care, including better access, broader task profiles for GPs, and more medical equipment lead to higher rates of admission for diabetes. Perhaps many diabetes related admissions are appropriate?

Hospital bed supply appeared to be a very important factor in increasing the use of hospitals!

So, if you want more hospital admissions, build more hospital beds and invest in disease specific management programs, especially those that have diabetes as the target illness, and decrease the continuity of care between each person and their GP.