CLUSTERING OF PRECONCEPTION MORBIDITIES IN SCOTLAND: A POPULATION-BASED STUDY

Sarjit Singh¹, Martin F Shaw¹, Deborah A Lawlor², Scott M Nelson¹, Rachel J Kearns¹

1University of Glasgow, 2University of Bristol

 

BACKGROUND

• Multimorbidity (MM) is defined as two or more chronic conditions in a person¹

• MM is associated with adverse maternal and neonatal outcomes²

• Preconception multimorbidity lacks a consensus definition, with current definitions overlooking shared mechanisms or pathophysiology

• We aimed to identify condition clusters, explore shared mechanisms, and assess associations with adverse maternal / neonatal outcomes

 

METHODS

• A population-based study of all nulliparous women delivering in Scotland from Jan 2010 to May 2023

• Chronic conditions defined by the Chronic Condition Indicator Refined system³; chronic prescriptions defined as >4 prescriptions for a drug class in 1 year

• Clustering of chronic conditions/prescriptions using Ward’s D2 method⁴

• Outcomes: maternal/neonatal readmission, critical care admission, or death up to 6 weeks post-delivery

• Statistical analysis: logistic regression adjusting for maternal age, smoking, drug use and ethnicity

 

RESULTS

• 248,817 nulliparous women delivered in our study period across the whole of Scotland

• 119,014 (47.8%) had a chronic condition / prescription allowing them to be clustered

• We identified 20 distinct clusters

• Most common clusters:

   • Cluster 14: Obesity with depression (30,075 25.3%)

   • Cluster 12: Isolated obesity (26,387 22.2%)

   • Cluster 11: Atopy (10,065 8.46%)

   • Adverse outcomes in 7,730 (3.11%) mothers and 45,805 (18.4%) neonates.

• Most adverse events were in cluster 13 (Figure 1):

   • Cluster 13 captured endocrine diseases (including diabetes, thyroid, adrenal pathologies and prescriptions)

   • Maternal aRR: 3.21 (95% CI: 2.61 - 3.94)

   • Neonatal aRR: 3.29 (95% CI: 3.01 - 3.59)

 

CONCLUSIONS

• We identified 20 clusters of comorbidities

• We observed a disproportionately high likelihood of maternal and neonatal adverse outcomes in women with preconception endocrine disease

• Further work will assess how these clusters of comorbidities interact and aid antenatal risk assessment

Refences

1 – Lee SI,, et al. Epidemiology of pre-existing multimorbidity in pregnant women in the UK in 2018. BMC Pregnancy Childbirth 2022; 22:120

2 – Brown HK, McKnight A, Aker A. Association between pre-pregnancy multimorbidity and adverse maternal outcomes. Journal of Multimorbidity & Comorbidity 2022

3 – Healthcare Cost and Utilization Project. Chronic Condition Indicator Refined. 2023. https://hcup-us.ahrq.gov/toolssoftware/chronic_icd10/chronic_icd10.jsp

4 – Ward JH. Hierarchical Grouping to Optimize an Objective Function. Journal of the American Statistical Association, 1963 58, 236–244.