Introduction

Children admitted to pediatric wards or intensive care units are stressed due to separation from their parents, the strange environment, and fear of painful procedures/treatment [47]. A prevalence of 83.3 % pre-operative anxiety was observed amongst children during their stay in operative room [12]. Adverse psychological and behavioral changes such as decrease in children’s self-esteem and emotional well-being, increased anxiety, sleep disturbances, and social isolation have been observed not only during hospital stay but also in 25 % of children, 1-year post-discharge from pediatric intensive care unit [11, 37]. A recent systematic review on the same topic identified negative psychological sequelae amongst children [38]. Not only in children but also parents face similar stress and anxiety in these situations. High parental anxiety could be observed if their child is admitted in intensive care unit, where nearly 62 % had anxiety that was significantly higher than a validated sample of patients with generalized anxiety disorder [33].

Clowns in the hospitals, otherwise called as clown doctors, interact with the pediatric patients and/or their parents to reduce their apprehension, fear and blues, thereby ease their recovery [26]. Clown doctors have been shown to be very good at distraction therapy from pain-inducing source, especially in children [2]. Theatrical intervention and humor in the treatment of patients have been documented as early as thirteenth century [18]. It has also been scientifically proven that hearing jokes from medical clowns was associated with increased activity in the network of subcortical regions, including the amygdala, the ventral striatum, and the midbrain, which are involved in experiencing positive reward [5]. Considering the lacunae of a systematic review on this topic, we carried out the present study with an objective of systematically compiling the existing evidence regarding the utility of medical clowns in various pediatric conditions and applying the principles of meta-analysis on the eligible outcome measures.

Methods

Information sources and search strategy

The protocol for this review was registered with international prospective register of systematic reviews (PROSPERO) with the registration number CRD42016041248. The review protocol can be accessed at http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42016041248. A thorough literature search was conducted and was completed on 14 June 2016. The primary data base used was Medline (via PubMed), Cochrane central register of clinical trials, Database of Abstracts of Reviews of Effects and Google Scholar. The key words used were clown [tiab]. This search was further supplemented by hand searching of relevant references from review articles and other eligible studies. No limits were applied in the present review.

Eligibility criteria

Only those studies with randomized controlled design with the following requirements were included in the present study:

  1. 1.

    Type of participants—children who were either admitted in the hospital or underwent any invasive procedures such as intravenous cannulation or blood collection or minor surgeries under anesthesia

  2. 2.

    Type of intervention—hospital clown

  3. 3.

    Comparison—usual standard of care without clown intervention

  4. 4.

    Outcome—The primary outcome measures were the number of children with anxiety, the extent of anxiety measured by any scale and the extent of pain felt as measured by any scale. The secondary outcome measures were the number of children who cooperated, extent of cooperation measured by any scale, number of caregivers with anxiety, extent of anxiety felt by the caregivers, time taken for inducing anesthesia, number of children shifted from the planned inhalational to intravenous anesthesia, number of children requiring an increased requirement of anesthesia, number of children satisfied with the care provided, number of parents satisfied with the care provided, number of times anxiolytic drugs were used and number of attending interruptions by the hospital staff.

Study procedure

Two authors independently screened the data bases and reviewed the identified abstracts for suitability. Full-text articles were obtained following abstract screening for those found to be eligible to be included in the review. A pre-tested data extraction form was created and two authors independently extracted the following data from each eligible study: trial site, year, trial methods, participants, interventions, and outcomes. Disagreement between the authors was resolved through discussion. The extracted data were analyzed using non-Cochrane mode in RevMan 5.3 software. The methodological quality of eligible trials was independently assessed by both the authors using the Cochrane collaboration’s tool for assessing the risk of bias. We followed the guidance to assess whether trials took adequate steps to reduce the risk of bias across six domains: sequence generation, allocation concealment, blinding (of participants, personnel, and outcome assessors), incomplete outcome data, selective outcome reporting, and other sources of bias. The judgment was categorized into low, high or unclear risk of bias [23]. For continuous outcome measures, standardized mean differences (SMD) and risk ratio (RR) for categorical outcomes were considered for the final assessment from individual studies. SMD was chosen as a measure of pooled results considering the variability observed in the measuring scales for continuous outcomes. The SMD was categorized as small, medium, and large based on the thresholds 0.2, 0.5, and 0.8, respectively, as suggested by Cohen’s [10]. Ninety-five percent confidence interval (95 % CI) was used to represent the deviation from the point estimate for both the individual studies and the pooled estimate. The heterogeneity between the studies were assessed using forest plot visually, I2 statistics wherein more than 30 % was considered to have moderate to severe heterogeneity and Chi-square test with a statistical P value of less than 0.10 to indicate statistical significance. Random effect models were used in case of moderate to severe heterogeneity otherwise fixed effect models were generated. Egger’s Funnel plot was used to assess publication bias for those outcomes that have at least ten studies. The present meta-analysis was conducted and presented in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines [31].

Results

Search results

A total of 91 studies were obtained from the electronic databases of which finally 19 [1, 3, 7, 9, 13, 15–17, 19–22, 25, 29, 30, 41–43, 48] were found eligible to be included in the present review (Fig. 1). A summary of the key characteristics of the included studies is mentioned in Table S1, available as supplementary file. Risk of bias of the studies included in the systematic review is depicted in Fig. 2. One of the included studies was a conference abstract [17] and so risk of bias could not be judged. Authors in the same study had displayed a video of clown doctors to the experimental group of children and the only outcome measure reported in this abstract was the anxiety score for children. Hence, we also carried out a sensitivity analysis for this outcome by excluding this study to see the impact of this data. Of the 19 studies, three [9, 21, 25] did not report the outcome measures appropriately to be included in the quantitative synthesis. The corresponding authors of these studies were sent an electronic communication requesting for the details, but did not respond. Hence, a total of 16 studies were included for the final meta-analysis. Publication bias could be assessed only for one of the outcomes—extent of anxiety experienced by children and no bias was observed (Fig. 3).

Fig. 1
figure 1

Study flow chart. A total of 91 studies were obtained with the search strategy of which 19 were included in the systematic review and 16 in the meta-analysis

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Fig. 2
figure 2

Summary of risk of bias of the included studies. Red circle with minus symbol indicates the absence of reporting specific element by the authors while green circle with plus symbol indicates reporting of the same. Festini et al. 2014 [31] was a conference abstract and none of the elements of risk of bias could be assessed

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Fig. 3
figure 3

Assessment of publication bias by Egger’s funnel plot. Publication bias was assessed only for the anxiety score in children and no bias was detected as evident by the symmetrical distribution of the effect estimates of individual studies

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Pooled results

Primary outcomes

Extent of anxiety experienced by children

A total of 11 studies that included 689 children compared the effect of clown therapy with the standard of care on the extent of anxiety felt by study participants. Seven studies used modified Yale pre-operative anxiety scale (m-YPAS) and one each had used facial affective scale, Likert scale, children anxiety, and pain scale—anxiety component and child surgery worries questionnaire to assess the same. The pooled SMD [95 % CI] for child anxiety score was −0.83 [−1.16, −0.51] favoring clown therapy (Fig. 4). Sensitivity analysis after removing the data from the conference abstract [17] did not influence the interpretation of pooled estimate {0.82 [−1.17, −0.47]}.

Fig. 4
figure 4

Forest plot of anxiety score with clown therapy in comparison to standard of care. A statistically significant reduction in the anxiety score was observed with the pooled estimate favoring the use of clown therapy

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Extent of pain felt during invasive procedures in children

Five studies compared pain felt during the procedures in a total of 257 participants. Three studies used visual analogue scale (VAS) and two employed numerical rating scale (NRS). Figure 5 depicts the forest plot of changes in the pain score and no significant difference was observed in the pooled estimate.

Fig. 5
figure 5

Forest plot of pain score with clown therapy in comparison to standard of care. No significant reduction in the pain score was observed with clown therapy in comparison to standard of care

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Number of children with anxiety symptoms

None of the included studies reported the number of children with anxiety symptoms individually in both the groups and hence analysis of this variable was not performed in the present meta-analysis.

Secondary outcome measures

Extent of anxiety experienced by parents

Eight studies compared the effect of clown therapy with standard of care on parental anxiety. Of these, all the eight (in a total of 489 study participants) assessed state anxiety of the parents while only four (in a total of 217 study participants) assessed trait anxiety additionally. A statistically significant reduction in state anxiety {SMD [95 % CI] −0.46 [−0.7, −0.21], Fig. 6} was observed with clown therapy in comparison to standard of care but not in the trait anxiety {SMD [95 % CI] −0.21 [−0.69, 0.28], Fig. 7}.

Fig. 6
figure 6

Forest plot of state anxiety experienced by parents with clown therapy in comparison to control. A significant reduction in the state anxiety was observed amongst parents with clown therapy in comparison to standard of care

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Fig. 7
figure 7

Forest plot of trait anxiety amongst parents with clown therapy in comparison to standard of care. No significant difference was observed in trait anxiety amongst parents with clown therapy in comparison to controls

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Number of children requiring the use of anxiolytics

Two studies in a total of 522 children reported the total number of children requiring the use of anxiolytics. The pooled relative risk was found to be 0.47 [0.15, 1.53] and was not statistically significant (Fig. 8).

Fig. 8
figure 8

Forest plot of relative risk of anxiolytic use between the groups. No significant risk of anxiolytic use was observed with clown therapy in comparison to control group

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Other secondary outcome measures

None of the eligible studies included in this review reported number of children for inhalational but administered intravenous anesthetic agent due to non-cooperation, or those requiring increased anesthetic agents or children satisfied with the given care. Only one of the studies reported the time taken for induction of anesthesia, number of parents satisfied with the given care, number of interruptions by the healthcare staff and number of parents with anxiety, thus could not be used for the meta-analysis.

Discussion

We conducted the present study to compare the clinical utility of hospital clowns in comparison to standard of care to alleviate fear, anxiety and pain in children, who were either admitted in pediatric ward or undergoes invasive procedures in the form of intravenous cannulation or minor surgeries under anesthesia. We also studied the effect of clown therapy on parental anxiety. A total of 19 eligible studies were obtained. We found that clown therapy significantly reduces the anxiety experienced by children and state anxiety in parents. The size of the reduction in anxiety was found to be large with children and medium with parents in the present study.

We found that medical clowns are therapeutically useful to alleviate fear and anxious symptoms in admitted children. Good communication between healthcare staff and children, as well as their parents is an essential support to be offered, to ease stress in parents whose child is admitted in pediatric wards [45]. The presence of medical clowns supplements the support and strengthens the system. The Hamberg field survey was a nation-wide survey of clowns, parents and supporting staff in hospitals in Germany and concluded that clown intervention boosts morale and reduces stress in patients without any side effects [4]. The utility of medical clowns is more stressed when invasive procedures are being carried out in children such as intra-articular injection of corticosteroid in patients with juvenile idiopathic arthritis [34, 44]. Decreased stress and pain with a positive patient experience was observed when therapeutic clowns were offered in addition to nitrous oxide sedation for such children and their parents [44]. In fact, Dvory et al. [14] have shown that there was no need for sedation in children undergoing radionuclide scanning, when therapeutic clowns were present. Colville et al. [11] found that 63 % of the children discharged from pediatric intensive care unit reported at least one factual memory of their admission and 32 % reported delusional memories, including disturbing hallucinations, thus having post-traumatic stress disorder. Additionally, Muscara et al. [32] assessed various psychological reactions amongst parents and found that 49–54 % met the criteria for acute stress disorder; 15–27 % had clinical levels of depression and anxiety, and 25–31 % for general stress. So, we suggest that clown therapy should also be offered to parents of children admitted in pediatric ward and future studies should focus on generating evidence on this aspect. Medical clowns have also been shown to be effective in inculcating positive attitude in geriatric patients especially in dementia [28, 35], patients with psychiatric disorders [46] and those undergoing dialysis [6].

Ventures such as “Dream Doctors Project” in Israel and “Medical Clown Project” in the United States of America have been initiated that consists of individuals with a background in dramatic arts like acting, street theater and physical clowning, etc. with appropriate training to work in hospitals. All hospitals and especially those offering services to pediatric population, elderly and palliative care should make arrangements to employ such trained medical clowns. If such therapy cannot be offered to all the admitted children due to resource constraints, at least it should be offered to those at high risk of developing negative psychological sequelae, based on their level of illness severity and the number of invasive procedures they are exposed to [39]. Additionally, children rehabilitation centers also have similar stress environment where children suffer from lengthy separation from their parents and prolonged restricted activities [8]. A pilot study amongst disabled children observed that a more positive and fewer negative facial expressions and emotional disturbances during the clown intervention [24]. Authorities should also take efforts in employing hospital clowns to improve mental stability of residents in such institutions. Appropriate training of clowns is essential to convert them to hospital clowns so that they learn the right approach to babies, children, adolescents, and their parents who will be sensitive given the environment [27]. Medical clown measure is a self-reported questionnaire to assess the perception of clown’s presence [40]. It is a validated tool and future studies shall utilize this tool in addition to other measures to actually assess the impact of using medical clowns.

Hospital clowning is an interdisciplinary art with a wide variety of multiple skills such as humor, drama, music, and dance due to which a beneficial, therapeutic impact have been noted in patients [36]. To conclude, we found that hospital clowns play a significant role in reducing stress and anxiety levels of children admitted to hospitals as well as their parents.