This study provides information on service utilisation of older adults with an AUD as well as on particular characteristics and treatment outcomes of older adults in addiction care. Altogether, we found a low proportion of older adults in treatment for AUDs but highly positive treatment outcomes at treatment discharge. Older women and late-onset patients constitute a unique clientele, regarding sociodemographic, disorder- and treatment-related characteristics.
Access to addiction care and service utilisation among older adults
Although evidence suggests high treatment efficacy for older adults with AUDs [5, 6, 24] and German AUD treatment guidelines  recommend addiction treatment for older patients, the willingness of older people to utilise addiction care is low [6,7,8]. Based on the estimated number of 400,000 older adults with AUDs in Germany [5, 6, 12] our findings show that currently only about 3% of them are reached by addiction services. This is a much lower rate compared to the general adult population, where about 13–30% of those with an AUD seek some kind of addiction-related help [13, 38,39,40,41,42]. Keeping in mind that older adults account for about one quarter of the population but only for 7–10% of all AUD patients in addiction care, this affirms former notions of a significant underrepresentation of this population in addiction care [5, 6, 16, 18]. Consequently, this underlines the need for actions to better reach this clientele.
The fact that nearly all adults with an AUD (93%) are in contact with the primary care system  and considering the frequency with which older adults seek help for their multiple health problems, emphasises the important role primary care may play in the detection of AUDs and the initiation of adequate treatment [24, 43, 44]. The very low referral rates from medical doctors (and therapists) into addiction care, which have been found in this study, underline the need to intensify co-operations between addiction treatment facilities and primary care. Accordingly, the implementation of short screenings or special education and trainings for health practitioners may promote the recognition of AUDs among older adults in primary care settings . Likewise, the low proportion of referrals by families reflects the finding that relatives of older adults with an AUD often do not address the problem due to shame, denial, misperceptions or even a lack of awareness of the alcohol abuse . This emphasises the importance of promoting social environmental support (family-doctors, family, etc.) in encouraging help-seeking behaviour among older adults. Furthermore, the lack of referrals by age-specific institutions, such as nursing-homes, where alcohol misuse or dependence is also common  emphasises the need to focus on special services for older adults, and to establish networks and co-operations with these institutions which may help to reach this clientele.
Apart from these structural improvements health care utilisation might, amongst others, also be increased by the diversification of treatment approaches or a shift in treatment goals from abstinence-oriented treatment to moderate drinking. This may lead to an increased acceptance of addiction treatment and interventions . Thus, especially in the case of less severe disorders, a return to moderate alcohol consumption might be an appropriate treatment goal.
Characteristics of older AUD patients in treatment
The overall higher proportion of women among older patients with AUDs stands in marked contrast to the higher proportion of men with AUDs in the general population [10,11,12]. This may be explained by the higher proportion of women in this age group . Otherwise, the high number of women with late-onset of an AUD may account for this divergent gender distribution. In our sample older women and late-onset patients were more frequently widowed and living alone than their male counterparts. This is in line with former findings that, among women, AUDs often develop later in life due to changes in life circumstances, such as the loss of a partner, or children leaving the parental home . The high proportion of older patients in retirement reflects another specific living condition, which can result in a lack of social control or more time spent engaging in alcohol drinking activities, and thus contribute to the development of problem alcohol use in older age [16, 22]. Here again, women and late-onset patients might be more at risk, as in our sample, they showed less involvement in the labour market. The high educational level among older AUD patients in our sample is consistent with former findings [6, 10] which show a positive relation between educational level and alcohol consumption among older persons. On the other hand, seeking treatment seems also to be positively associated with educational level [47, 48] and could therefore explain the high educational levels in this treatment sample.
Disorder- and treatment-related characteristics
Among persons with AUDs, seeking help seems to be influenced by the severity of the disorder [38,39,40,41]. Accordingly, persons with less severe AUDs often remain untreated . With regard to severity of the AUD our findings seem to indicate that early-onset AUD patients show a longer and more complicated disorder- and treatment history and are rather comparable to younger patients with regard to their disorder-related characteristics. In contrast, late-onset AUD patients seem to be affected less severely with regard to a later AUD onset, shorter duration of the AUD and less previous treatment. This is in accordance with former findings, which found that late-onset AUD patients are affected less severely, even with regard to physical and psychical comorbid conditions [16, 22]. Generally, older patients show a lower burden of comorbid substance use disorders. Among older adults, only tobacco and sedatives use disorders were found comorbid with AUD. The latter is in accordance with the reported high use of medications among older adults . The link between psychological problems and problem use of alcohol [20, 21, 50] is also evidenced in our sample by the high additional burden of comorbid mental disorders, especially among older women. In general, disorder-related characteristics seem to differ in particular between early- and late-onset AUD patients and not so much between age groups. The found differences between the different groups of older AUD patients may be important for tailored treatment approaches focusing on the unique characteristics of this populations.
Treatment outcomes of older patients
With regard to abstinence at discharge, treatment adherence and treatment success, our findings confirm former studies which have found that older adults benefit highly from treatment, even more than younger patients [5, 6, 24, 37]. The proportion of regularly terminated treatment episodes among older patients is higher than in the sample of younger AUD patients and the majority of older patients’ outcomes were improved or successful at treatment discharge. This is also reflected in the abstinence rates which, at discharge, have almost doubled those at treatment entry. Accordingly, follow-up studies in German addiction care have found abstinence rates for AUD patients after one year between 41 and 79% in inpatient and 31–67% in outpatient settings [51, 52]. Thus, evidence indicates that the good treatment results among older adults remain relatively stable over time [51,52,53]. Contrary to former findings [5, 23, 24], we did not observe significant differences regarding the treatment outcomes of early- and late-onset patients.
Although the monitoring system of addiction care, with its large sample size, widespread coverage of treatment centres and detailed standardised documentation, offers a valuable base for exploratory descriptive investigations, the aggregated data format constitutes a limitation with regard to possible statistical analyses. Due to the high sensitivity of chi2 tests in such large sample sizes, descriptive analysis can be considered more sensible in this context and with regard to our study aim. For a test, we conducted chi2 tests for some of the variables, but, as assumed, all results were highly significant (e.g., “gender”: chi2: 695303.9042, p < .00001). For more sophisticated analyses, individual data need to be collected and investigated.
A further limitation lies in the operationalisation of treatment outcome assessment, which is only based on the subjective assessment by the therapist at discharge. No information is available on common outcome measures, such as rates of relapse or toxicological screenings at discharge or at a follow-up assessment. Integrating those measures when investigating large treatment populations would be an interesting subject for future research.
With regard to the specific study aim, it has to be mentioned that some examined variables are related to age and are likely to be confounded by cohort effects. Nevertheless, the aim of the study was not to quantify differences between younger and older patients with AUDs, but to gain insight into the older clientele and its characteristics. Another more critical confounder, which may explain the low number of older adults in alcohol treatment, lies in the decline of AUDs with age, due to the lower life-expectancy of people with AUDs and the high rate of deaths before age 65 . Consequently, severity of disorder may also be influenced by this factor, as those who live beyond age 65 often show less severe disorders or have limited their consumption due to poor health, reduced tolerance or sequelae [6, 11]. Against this background the differentiation between early- and late-onset patients was important. Although recall bias is likely to pose a problem when it comes to investigating the exact age of AUD onset, evidence points to differences between groups of patients with early and late onset of the AUD. Thus, we examined patients with onset before and after the age of 45 years which resulted in two large samples: early-onset patients with a mean onset of the AUD at age 29 and late-onset patients with an onset at age 54. This also suggests that these two samples likely differ with regard to the circumstances that led to their problematic drinking.