PT  - JOURNAL ARTICLE
AU  - C H Mercer
AU  - K G Jones
AU  - A M Johnson
AU  - R Lewis
AU  - K R Mitchell
AU  - K Gravningen
AU  - S Clifton
AU  - C Tanton
AU  - P Sonnenberg
AU  - K Wellings
AU  - J A Cassell
AU  - C S Estcourt
TI  - How can we objectively categorise partnership type? A novel classification of population survey data to inform epidemiological research and clinical practice
AID  - 10.1136/sextrans-2016-052646
DP  - 2017 Mar 01
TA  - Sexually Transmitted Infections
PG  - 129--136
VI  - 93
IP  - 2
4099  - http://sti.bmj.com/content/93/2/129.short
4100  - http://sti.bmj.com/content/93/2/129.full
SO  - Sex Transm Infect2017 Mar 01; 93
AB  - Background Partnership type is a determinant of STI risk; yet, it is poorly and inconsistently recorded in clinical practice and research. We identify a novel, empirical-based categorisation of partnership type, and examine whether reporting STI diagnoses varies by the resulting typologies.Methods Analyses of probability survey data collected from 15 162 people aged 16–74 who participated in Britain's third National Survey of Sexual Attitudes and Lifestyles were undertaken during 2010–2012. Computer-assisted self-interviews asked about participants' ≤3 most recent partners (N=14 322 partners/past year). Analysis of variance and regression tested for differences in partnership duration and perceived likelihood of sex again across 21 ‘partnership progression types’ (PPTs) derived from relationship status at first and most recent sex. Multivariable regression examined the association between reporting STI diagnoses and partnership type(s) net of age and reported partner numbers (all past year).Results The 21 PPTs were grouped into four summary types: ‘cohabiting’, ‘now steady’, ‘casual’ and ‘ex-steady’ according to the average duration and likelihood of sex again. 11 combinations of these summary types accounted for 94.5% of all men; 13 combinations accounted for 96.9% of all women. Reporting STI diagnoses varied by partnership-type combination, including after adjusting for age and partner numbers, for example, adjusted OR: 6.03 (95% CI 2.01 to 18.1) for men with two ‘casual’ and one ‘now steady’ partners versus men with one ‘cohabiting’ partner.Conclusions This typology provides an objective method for measuring partnership type and demonstrates its importance in understanding STI risk, net of partner numbers. Epidemiological research and clinical practice should use these methods and results to maximise individual and public health benefit.