Do financial barriers to access to primary health care increase the risk of poor health? Longitudinal evidence from New Zealand

Primary health care policies in New Zealand, as in many countries, have focused on reducing barriers to access. Financial barriers to obtaining timely health care, while not the only important barriers, are amongst the most important, and are amenable to policy reforms. There is little robust empirical evidence about the extent to which cost related barriers are associated with adverse health outcomes. Past evidence is limited to cross-sectional studies of selected groups, selected primary health care services, and to cross-sectional studies that are susceptible to unmeasured confounding bias. Using fixed effects regression modelling and data from 17,363 participants with at least two observations in three waves (2004–05, 2006–07, 2008–09) of the SoFIE-Health panel data, this study examines the impact of financial barriers to access to primary health care (general practitioner and dentist) on health status using a longitudinal national panel study of adult New Zealanders. Self-rated health (SRH), physical health (PCS) and mental health summary scores (MCS) were the health measures. The two exposures were: not seeing 1) the doctor and 2) the dentist because of cost at least once during the preceding 12 months. We also tested for interactions between the exposure (deferral of care) and age, gender, ethnicity and three health outcomes. For all outcomes, after adjusting for time-varying confounders, health deteriorated as the number of waves increased in which a non-visit was reported. Moreover, the effect size for any health deterioration was greater for deferring a dentist visit than for deferring a physician visit. Except gender and age (for MCS and doctor visits), and gender and ethnicity (for SRH and dentist visits) we did not find any evidence of interactions. These results support policy responses focussed on decreasing financial barriers to access. In the New Zealand context this finding is particularly important for dental care.