Oral health status and oral health-related quality of life: a cross-sectional study of clients in an Australian opioid treatment program

Study design

This cross-sectional study adopted an exploratory approach to investigate the oral health status and OHRQoL among clients enrolled in an OTP. Non-random convenience sampling was utilised, involving clients from the OTP operating at three Australian clinics, one private and two public clinics. The public clinics, operated by a local health district of Northern Sydney, offered cost-free opioid treatment services during normal office hours. In contrast, the private clinic had extended operational hours to cater to those with work commitments. Data collection took place during four half-day sessions at each clinic, spanning different days of the week from March to April 2023. Approval for this study was obtained from the Northern Sydney Local Health District Human Research Ethics Committee (2022/PID02987).

Participant recruitment

A collaboration was established with Drug and Alcohol Services and Oral Health Services which aimed to broaden the research’s reach and facilitate access to the OTP clients. OTP clients were informed by clinic nurses about the opportunity for a free oral health assessment conducted by the oral health team with the incentive of receiving complimentary oral hygiene products. Upon obtaining verbal consent, clients were directed to the assigned oral health professionals for oral health assessment and questionnaire administration. This collaborative approach not only sought to engage study participants effectively but also provided them with tangible benefits to promote their oral health.

Data collection

Statistical analysis

Descriptive statistics summarised data, presenting means and standard deviations for normal data and median and ranges for skewed or ordinal data. Proportions were presented with a 95% CI. Pearson’s correlation coefficient and linear regression were used to assess the association between OHAT and OHIP-14. T-tests and ANOVA were used to compare oral health status across demographics.

Exploratory analysis utilised binary logistic regression and Poisson regression to analyse the likelihood and extent of impact. Adjustments for confounding variables were considered in the study. All statistical tests were conducted at a significance level of 0.05, and the analyses were performed using STATA version 17.0.

Sample characteristics

A total of 75 OTP clients participated in the study, with the sample drawn from a private clinic (n = 20, 26.7%), public clinic 1 (n = 36, 48.0%) and public clinic 2 (n = 19, 25.3%). Table 1 provides an overview of the demographic characteristics of the study participants. Most participants were male (n = 56, 74.7%) and unemployed (n = 56, 74.7%). The mean age of participants was 44.7 years (s.d. = 12.34), with ages ranging from 18 to 72 years.

Substance use and opioid treatment history

Table 2 presents an overview of the substance use and opioid treatment history of the study participants. The analysis revealed that the mean age at the start of substance use was 19.9 years (s.d. = 7.80), with approximately 90% of the participants reporting duration of substance use exceeding 10 years. Approximately 45% of the participants were engaged in opioid treatment for more than 5 years.

Smoking and alcohol consumption

More than 80% of participants reported a history of smoking. In addition, 10.67% of the participants reported daily alcohol consumption. Analysis revealed no significant difference in oral health severity scores across levels of alcohol consumption (P = 0.070) or smoking history (P = 0.530) as shown in Fig. 1.

Fig. 1.

Box plot of total OHAT and total score across gender, education, employment status, alcohol consumption and smoking history.

In terms of quality of life, no significant differences were observed based on smoking status (P = 0.756). However, a statistically significant difference in OHIP-14 severity scores was noted among different categories of alcohol consumption (P = 0.012), indicating variations in the quality of life based on alcohol intake. Specifically, individuals consuming alcohol two to three times a week exhibited a significantly lower mean OHRQoL score (mean OHIP-14 = 23.18, 95% CI: 14.96–31.40), indicating better OHRQoL compared to those who consumed alcohol daily (mean OHIP-14 = 33.38, 95% CI: 23.73–43.02), two to three times a month (mean OHIP-14 = 39.43, 95% CI: 29.12–49.74), or those who never consume alcohol (mean OHIP-14 = 38.14, 95% CI: 34.25–42.04).

Oral health assessment results (OHAT)

Table 3 summarises the OHAT scores. The total score ranged from 0 to 16, with a mean score of 6.93 (s.d. = 2.46). Notably, lip changes were observed in 97% of participants, while 70% exhibited changes in saliva. Approximately half of all participants had four or more decayed or broken-down teeth and reported dental pain. Furthermore, one-third of the participants exhibited the presence of food debris tartar or plaque in most areas of their mouth, and gum and tissue changes were detected in two-thirds of the participants.

Oral Health Impact Profile (OHIP-14)

Table 4 summarises the prevalence, extent and severity of the OHIP-14. Table 5 presents prevalence rates and their associations with sociodemographic and drug use variables. In the sample, 69.33% (95% CI: 58.17–78.61) scored positive for prevalence. Logistic regression results indicated a statistically significant association with age. Those aged 30–49 years or 50 or older years showed significantly higher odds of experiencing a negative impact compared to those under 30 years (adjusted odds ratio (OR) = 20.36, 95% CI: 2.25–184.60 for 30–49 years, adjusted OR 26.60, 95% CI: 2.63–269.41 for 50 or older years). Additionally, the odds of experiencing a negative impact increased by 1.85 times with one-unit increase in the OHAT score, indicating poorer oral health (adjusted OR = 1.85, 95% CI: 1.38–2.49, P < 0.001). This association suggests that poorer oral health, as assessed by OHAT, correlates with a higher likelihood of adverse impacts on quality of life, as measured by OHIP-14. However, caution should be exercised in interpreting this association, as OHAT and OHIP-14 measure different domains of oral health. While the comparison enhances our understanding of the broader impact of oral health on overall well-being, further validation and contextualisation of these findings may be warranted.

The perceived extent of the impact, calculated by the total number of items reported at least ‘often’ (codes 3 and 4), showed a mean of 3.78 (s.d. = 3.98). The likelihood ratio test revealed significant overdispersion (P < 0.05) in the Poisson regression model, indicating the need to apply a negative binomial regression model. The summarised findings are presented in Table 6, illustrating the association between socio-demographic and drug use variables and extent scores. Specifically, the 30–49 years and 50 years or more age groups exhibited a significantly higher extent of negative impact than the younger age group (less than 30 years) (incidence rate ratio (IRR) = 33.76, 95% CI: 4.09–78.43 for 30–49 years and IRR = 34.00, 95% CI: 4.04–286.02 for 50 years or more). Additionally, poor oral health, as measured by OHAT, was significantly associated with a higher extent of negative impact on quality of life (IRR = 1.27, 95% CI: 1.14–1.42, P < 0.001).

The mean severity score was 20.95 (s.d. = 14.44). A positive and statistically significant correlation was found between oral health (OHAT score) and OHRQoL, as measured by the OHIP-14 scale (n = 75, r = 0.584, P < 0.001), as depicted in Fig. 2. The quantified effect indicated that a one-point increase in the OHAT score was associated with an average increase of 3.43 points (95% CI: 2.43–4.42) in the OHRQoL score (P < 0.001). After adjusting for confounding factors such as age at commencement of substance use, gender and education level, the relationship remained statistically significant with a one-point increase in the OHAT score (representing poorer oral health) associated with a 3.11-point increase (95% CI: 1.91–4.29) in the OHRQoL score (P < 0.001).

Fig. 2.

Scatter plot of oral health quality of life and oral health status.

Oral health assessment insights

The assessment of oral health status using the OHAT revealed several concerning findings. The mean OHAT score of 6.93, out of a possible score of 16, reflects observed changes and highlights areas of weakness that necessitate careful monitoring for potential oral health issues. A higher OHAT score reflects a greater number of oral health issues or more severe problems. Approximately 70% of the participants displayed signs of reduced saliva production which can lead to increased plaque accumulation and acidification of the oral environment, contributing to the development of dental caries (González-Aragón Pineda et al. 2020). Furthermore, the presence of decayed or broken-down teeth and reported dental pain in approximately half of the participants highlights significant oral health challenges faced by this population group. It is noteworthy that in terms of medications, methadone hydrochloride comes in different formulations, including sugar-free Biodone Forte and sugar-based Methadone Syrup. Buprenorphine is offered in tablet and film forms for sublingual administration, with the film version using glucose syrup and citric acid to mask the bitterness of the active agent. There are also long-acting subcutaneous injectable buprenorphine options administered by either weekly or monthly injections. These medications aim to reduce illicit opioid use and enhance overall health. While it is crucial to be aware of the sugar content in these medications (excluding injectable buprenorphine), it is also important to note that oral health issues are influenced by various factors, including oral hygiene practice and regular checks, not solely the medication itself.

These findings underscore the importance of addressing these widely reported oral health problems affected by opioid use (Cossa et al. 2020). Effectively addressing these issues necessitates the implementation of targeted interventions focused on alleviating dental pain, promoting preventive measures, and providing restorative treatment.

Prevalence, extent and severity of oral health impact (OHIP-14)

This investigation revealed a notable prevalence of oral health impact, with 69.33% of individuals reporting items as ‘often’ (3) and ‘always’ (4), highlighting issues related to physical pain and psychological discomfort. Notably, our study found a higher prevalence of oral health impact compared to previous studies on PWID (48%) (Truong et al. 2015) and methamphetamine users (35%) (Abdelsalam et al. 2023) in Australia. The mean extent of the impact, representing the number of items reported at less ‘often’ (3) and ‘always’ (4) was 3.78, significantly higher than in previous studies (PWID study: 2.5, methamphetamine cohort study: 1.58) (Truong et al. 2015; Abdelsalam et al. 2023). This underscores the urgent need for comprehensive oral health interventions to address the broad-reaching effects of poor oral health. Additionally, the mean severity, representing the total sum of participant responses, was 20.95, substantially higher than previous studies (PWID study: 13.5, methamphetamine cohort study: 9.63), indicating significant disparities. These differences may stem from various factors, including differences in study population (sample size and demographics), variations in oral health behaviours, drug use patterns, substance compositions, access to oral health care and measurement methods. Future research is needed to comprehensively understand the specific factors contributing to these disparities and to assess the nuanced impact of opioid treatment on oral health outcomes.

Association with age

The analysis demonstrated a statistically significant association between age and prevalence and the extent of negative impact among OTP clients. Specifically, clients aged 30–49 years and those aged 50 years or older had significantly higher odds of experiencing a negative impact on their quality of life due to oral health issues. This suggests that older clients may be more susceptible to the consequences of poor oral health. A previous study (Roe et al. 2010) has similarly found that the impact of drug use on health status and quality of life escalates with age, highlighting the importance of providing supportive services for treatment and care within this population group.

Influence of smoking and alcohol consumption

In examining the OTP clients, the study explored the influence of alcohol consumption and smoking history on the participants. Over 80% disclosed a history of smoking while approximately 50% reported regular alcohol consumption, consistent with previous findings (Sordo et al. 2017) showing higher rates of smoking and alcohol consumption among individuals receiving opioid treatment compared to the general population.

Although no significant association was found between smoking history and oral health status or quality of life, intriguingly, participants who consumed alcohol two to three times a week exhibited notably higher quality of life scores. This suggests that the frequency of alcohol consumption may influence the oral health-related quality of life, possibly due to factors such as social engagement and support (Hajek et al. 2017). However, further research is needed to fully understand this relationship.

Correlation between OHAT and OHIP and its implications for policy

An exploratory analysis revealed a robust positive correlation between participants’ OHAT and OHIP-14 scores. Specifically, a one-unit increase in OHAT score corresponded to 1.85 times higher odds of experiencing a negative impact on quality of life (OR = 1.85, 95% CI: 1.38–2.49, P < 0.001). This correlation suggests that OHIP-14, which measures self-reported oral health-related quality of life, could potentially serve as a useful proxy for the OHAT, indicating that OHIP-14 alone might be sufficient for identifying oral health needs within an OTP setting.

Using OHIP-14 as a screening tool could be particularly advantageous in settings where clinical oral health assessments are not feasible. It enables OTP clinicians to identify clients with significant oral health issues, facilitating timely referrals and interventions without requiring specialised dental training. This underscores the potential of OHIP-14 for routine screening within OTP settings, ensuring early detection and management of oral health concerns. This approach could inform the development of targeted interventions and policies that prioritise oral health care as a component of holistic treatment strategies within OTPs. Integrating OHIP-14 into standard OTP procedures ensures that oral health is recognised as a critical aspect of overall well-being. Ultimately, this could lead to improved care and health outcomes for OTP clients.

Limitations

This study has notable limitations. Firstly, recruiting participants exclusively from three OTP clinics may limit the generalisability of the findings. Secondly, relying on self-reported quality of life measures, while common, introduces potential subjective bias, as individuals’ perceptions can be influenced by personal feelings, attitudes and experiences. This may result in data that does not accurately reflect objective reality. Additionally, the relatively small sample size limits result precision. Despite these considerations, the study contributes valuable insights into oral health and OHRQoL among individuals in an OTP, offering a foundation for future research in this critical area.