A total of 131 articles were reviewed, and 12 met inclusion criteria (Table 1). The quality of included studies was generally low consisting, primarily of observational and quasi-experimental studies with only one randomized controlled trial.

Eight studies were conducted in the USA, two in Brazil, and two in Europe. Primary study sites were community hospitals, three included long-term acute care hospitals, and one study was in the outpatient primary care setting. One study examined a pediatric inpatient population [18], the remainder focused on adults.

The most common ASP intervention was prospective audit and feedback (PAF) included in 58% (7/12) studies.

The most common primary outcome was antimicrobial consumption reported in 5 of the included studies [11, 13, 14, 16, 20]. Four of the five studies demonstrated a statistically significant decrease in antimicrobial consumption with the implementation of telehealth antimicrobial stewardship [11, 13, 14, 16].

One study demonstrated a statistically significant decrease in antimicrobial prescriptions for upper respiratory tract infections in the outpatient setting [17]. A separate study examined effects on compliance with local guidelines with a statistically significant increase in the rate of adherence [15]. One study demonstrated a significant decrease in isolation of multi-drug resistant organisms [18]. One study found a statistically significant decrease in hospital-acquired Clostridioides difficile infection as a secondary outcome [14].

A single study expressed concern the local private practice ID physician would experience decreased financial compensation from lower consult volume with the implementation of telestewardship and evaluated the effect on ID consultations. They found a 40% increase in consultation following telehealth antimicrobial stewardship implementation [13]. Another study examined the time commitment required to perform telestewardship and found an average of 3.6 h per week of time from a remote ID pharmacy resident [22].

Of the examined studies, 83% (10/12) of telehealth antimicrobial stewardship programs consisted of a remote ID physician (one study utilized an internal medicine trained associated medical director [19], and another consisted of pharmacists [22]) and 25% (3/12) included a remote pharmacist [14, 20, 22]. One-third (4/12) of local sites created a local ASP team consisting of local providers, infection prevention nurses, and pharmacists [12, 16, 17, 23]. The other two-thirds only utilized local providers communicating with the remote ASP team.

Studies included between 1 and 4 remote ID physicians, 2 studies employed ID-trained pharmacists [14, 22], with one study included pharmacists with unspecified levels of training [20].

The size of hospitals examined ranged from 50 beds up to 2000. The average number of remote ASP providers to hospital beds was one provider for every 234 beds. The number of full-time-equivalents dedicated to remote antimicrobial stewardship was not routinely reported. The exact ratio of remote ASP providers to hospital bed size is unknown although it should be noted that only three of the eleven (27%) inpatient studies met the goal for traditional ASP programs of 1.0–1.5 FTEs per 100 hospital beds that has been described [24, 25]. CMS proposes a minimum of 0.10 physician FTEs along with 0.25 pharmacy FTEs for a “moderate size hospital” (defined as 124 beds), although acknowledges that 1.0 physician FTEs and 0.5 pharmacies FTEs may be more effective [4••].

On average, 64.6 interventions were performed per remote provider per month for the 9 studies where this could be determined. It should be noted that the reporting of interventions was not standardized among publications.

The primary modalities of communication were telephone or videoconferencing along with electronic medical record documentation. Two studies from the same author developed web-based platforms [11, 15], three communicated via secure email [11, 14, 15], and one via secure SMS messaging [15].

There was a wide variance in the provider acceptance rate of remote ASP recommendations ranging from 11 to 100%. The studies with the lowest reported compliance rates lacked face-to-face communication with the local facility—one study relied on e-mail only communication providing a 48% acceptance rate [14]. An 11% acceptance rate was seen when the remote ASP personnel communicated via TheraDoc with a local pharmacist and had no direct communication with frontline providers [22]. The remaining studies that reported on acceptance rates included some form of face-to-face communication with local providers and had acceptance rates ranging from 73 to 100%. Among the three studies that developed a local antimicrobial stewardship team and provided acceptance rates, the average acceptance rate was 86.6%. Among the 5 studies that did not create a local ASP, the average was 66.5%. It is notable that the studies not employing local ASP representatives had significantly more variance of acceptance rates and included the two lowest acceptance rates of 11 and 48%.

A potential concern regarding telehealth intervention would be decreased financial compensation related to a decrease in local ID consultation. The one study that examined this demonstrated an increase in local consultation. No study reported a financial loss. Three studies reported on annual antimicrobial purchasing cost savings ranging from $13,907 to $142,630. One study reported a $17,411 savings in total hospital charges including, $10,073 in pharmacy charges over 4 months. No study directly addressed the cost of establishing or maintaining a telehealth ASP.