Efficacy and safety of metformin in the management of type 2 diabetes mellitus in older adults: a systematic review for the development of recommendations to reduce potentially inappropriate prescribing.

BACKGROUND: Metformin is usually prescribed as first line therapy for type 2 diabetes mellitus (DM2). However, the benefits and risks of metformin may be different for older people. This systematic review examined the available evidence on the safety and efficacy of metformin in the management of DM2 in older adults. The findings were used to develop recommendations for the electronic decision support tool of the European project PRIMA-eDS. METHODS: The systematic review followed a staged approach, initially searching for systematic reviews and meta-analyses first, and then individual studies when prior searches were inconclusive. The target population was older people (≥65 years old) with DM2. Studies were included if they reported safety or efficacy outcomes with metformin (alone or in combination) for the management of DM2 compared to placebo, usual or no treatment, or other antidiabetics. Using the evidence identified, recommendations were developed using GRADE methodology. RESULTS: Fifteen studies were included (4 intervention and 11 observational studies). In ten studies at least 80% of participants were 65 years or older and 5 studies reported subgroup analyses by age. Comorbidities were reported by 9 studies, cognitive status was reported by 4 studies and functional status by 1 study. In general, metformin showed similar or better safety and efficacy than other specific or non-specific active treatments. However, these findings were mainly based on retrospective observational studies. Four recommendations were developed suggesting to discontinue the use of metformin for the management of DM2 in older adults with risk factors such as age > 80, gastrointestinal complaints during the last year and/or GFR ≤60 ml/min. CONCLUSIONS: On the evidence available, the safety and efficacy profiles of metformin appear to be better, and certainly no worse, than other treatments for the management of DM2 in older adults. However, the quality and quantity of the evidence is low, with scarce data on adverse events such as gastrointestinal complaints or renal failure. Further studies are needed to more reliably assess the benefits and risks of metformin in very old (>80), cognitively and functionally impaired older people.

Thiazides in the management of hypertension in older adults - a systematic review.

BACKGROUND: Thiazides are commonly prescribed to older people for the management of hypertension. The objective of this study was to identify the evidence on the risks and benefits of their use among adults aged ≥65 years and to develop recommendations to reduce potentially inappropriate use. METHODS: Systematic review (SR) of the literature covering six databases. We applied a staged search approach, where each search was undertaken only if the previous one did not yield high quality results. Searches 1 and 2 identified relevant SRs and meta-analyses published up to December 2015 from all databases. Search 3 identified additional individual interventional studies (IS) and observational studies (OS) not identified by the preceding searches. We included all studies evaluating the effect of thiazides on patient-relevant outcomes in the management of hypertension with a sufficient number of participants aged ≥65 years or a subgroup analysis based on age. Two independent reviewers extracted data and carried out quality appraisal. Recommendations were developed using the GRADE methodology. RESULTS: Searches 1 to 3 were performed. We included 34 articles reporting on 12 IS and 4 OS. Mean ages ranged from 59 to 83.8 years. Four studies had performed a subgroup analysis by age. Information on comorbidity, polypharmacy and frailty of the participants was scarce or not available. The IS compared thiazides to placebo or other antihypertensive drugs and evaluated cardiovascular endpoints or all-cause-mortality as primary outcomes. The OS investigated the association between thiazide use and the risk of gout, fractures and adverse effects. Our results suggest that thiazides are efficacious in preventing cardiovascular events for this population group. Low-dose regimens of thiazides may be safer than high-dose (low quality of evidence), and a history of gout may increase the risk of adverse events (low quality of evidence). Three recommendations were developed. CONCLUSIONS: The use of low dose treatment with thiazides for the management of hypertension in adults aged 65 and older seems justified, unless a history of gout is present. The quality of the evidence is low and studies rarely describe characteristics of the participants such as polypharmacy and frailty. Further good quality studies are needed.