Background
Home storage of medicine is a public health problem worldwide, which occurs because of improper utilization of medicines and/or non-adherence with drug therapy that consequently affects health, environment, and healthcare services [
1‐
6]. Although timely access to medicines is essential, there are some global concerns regarding unnecessary storage and inappropriate usage of medicines as well as unsafe disposal of leftover medicines [
7‐
11]. During past years, medicine utilization pattern has changed, which consequently leads to greater purchasing volumes and excessive accumulation at home [
12]. According to the World Health Organization (WHO), more than 50% of medicines are inappropriately prescribed and dispensed, which causes unnecessary storage [
13]. Therefore, WHO (2011) calculated that about 24.9% of the total health expenditure or 1.4 to 1.63% of Gross Domestic Product worldwide were spent on medicines [
14]. In Asia, a large proportion of out of pocket payments is spent on medicines. For example, in India, Bangladesh, and Vietnam, this share is calculated as 70% [
15]. In addition, households in Saudi Arabia spent a total of US $150 million on medicines that were never consumed [
16]. Garg et al. in their study has reported that three-fourth of out-of-pocket expenditures (74% rural and 67% urban) is drug-related [
17]. In China, the share of medicine expenses from GDP has raised more than up to 320 times since 1980 [
18]. Such observations only indicated the immediate consequences of inappropriate supply and demand of medicines, whereas further concerns would be attached to the risk of inappropriate storage and disposal. For example, accidental intoxication, inappropriate self-medication, the presence of pharmaceutical ingredients in waterways as environmental pollutants, accidental poisoning of wildlife, and risk of antibacterial resistance can be named in this regard [
8‐
10,
19‐
21].
By reviewing the medicine utilization chain, it should be clarified that unpleasant outcomes to both individuals and societies arise from several sources. Accordingly, it usually starts with over prescription by physicians [
9,
22,
23]; then continues through making improper decisions such as over-purchasing [
12], non-adherence to treatment [
16,
23,
24], and saving medicines for future use [
3,
25,
26]; and finally lasts with inappropriate disposal [
27‐
31] . Several systematic reviews have been conducted to address the issue; for example, on self-medication practice [
32‐
38], medicine wastage [
7,
39], and disposal practices among households [
40,
41]. However, to the best of our knowledge, there were inadequate consensuses about global burden of medicine storage rate, modality, and the associated factors. Of note, only one systematic review was found investigating this issue, which studied medicine storage from 1999 to 2016 [
42]. The Authors included studies from different population groups (consisting of university students, hospital referrals, and urban residents), which according to our electronic search, 8 and 7 studies were found to be performed before and after 2016, so we believed that they are eligible to support this body of literature. Another important issue regarding this review is that because of the existing heterogeneity in sample population of the included studies, the authors were not able to estimate the global or regional prevalence of inappropriate storage, so they narratively reported medicine storage rate by drug names and types. Correspondingly, this type of reporting would subsequently limit the comparability of findings from different settings or regions [
43]. Our study was conducted to overcome the above-mentioned challenges through performing a comprehensive overview of recent literature. Three main contributions of this review could be highlighted as follows: First, we investigated further 15 household surveys that have been published before and since the last search date of Hussein’s review. Second, in this study, we estimated the global and regional burden of medicine storage and wastage. Third, in order to increase the international and regional comparability of medicine utilization findings, we reported the obtained results based on a standard methodology called ATC classification [
44].
This study aimed to include all available evidences obtained from literature for performing a focused examination of the prevalence and the associated factors affecting medicine storage among households. It is noteworthy that, medicine storage is a public health problem in both rural and urban areas; however, the prevalence of home storage was reportedly higher in urban households due to more facilities concentrated within these areas as well as easier access to medicines [
2,
45]. Therefore, due to this reason, we included household surveys that investigated and reported information about urban populations.
Discussion
This systematic review and meta-analysis included 20 published studies conducted on a total of 10,898 urban households across 18 countries. The majority of the articles were from Asia and Africa, three from Europe, and one from South America. The pooled prevalence rates obtained from the included studies was 77% (95% CI; 67–88) for medicine storage and 15% (95% CI: 0.08–0.21) for real wastage, suggesting most of the urban households worldwide have unnecessary home medicine storage.
In our systematic review, the paucity of studies from Western Europe and American countries should not lead to underestimate the problem in that region or it means that medicine storage and wastage are not relevant to them. Moreover, many studies have recently been published indicating that a significant amount of medicines remained unused in European and American communities where some parts of them were returned to pharmacies or health facilities and the rest of them were inappropriately disposed [
77‐
80]. We have not included these studies because of differences in their data collection method, while we believe that investigating their results would clarify many challenges in their societies.
Notably, 77% of households worldwide had storage, which was the highest rate among Southwest Asia (95%) and the lowest one in Sub-Saharan Africa (67%). Despite that the high prevalence among countries were explained by disease pattern and the associated health problems such as a high proportion Gastrointestinal tract medicines in Jordan [
62]; malaria and anti-infective medicines in Tanzania [
67], Iran [
75], Ethiopia [
73], Uganda [
23], and Nigeria [
25]; and cardiovascular and diabetes medicines in Palestine [
24], India [
68], and Mexico [
81]. However, in most of the countries, the medicine storage and wastage were due to inappropriate prescription practice and inadequate patient adherence to treatment [
3,
16,
23,
24,
27,
69,
73,
82]. Patient attitudes and social values were mentioned as underlying factors stimulating medicine storage and wastage in different settings. According to the studies performed in Saudi Arabia, Kuwait, UAE, Qatar, Oman, and India, patients gratify drug prescription as the outcome of their visit to public health facilities [
16,
68]. The role of patient’s attitudes has been confirmed in studies by Hu et al. and Norris et al., where immigrants from developing countries such as China, India, Korea, and Egypt had different perceptions towards accessing and use of medicines compared to European and American counterparts [
83,
84]. Gedif et al. in their study attributed the lower prevalence rate of medicine storage among Ethiopian households to the community’s confidence on traditional medicine relative to pharmaceutical products [
45].
This review also found some evidences confirming that expired medicines are being used by households in low- and middle-income countries [
25,
69]. Dayom et al. reported that more than 97% of expired medicine items found in households are either being used or are kept for future use [
25]. As well, the same evidence has been reported from high-income countries [
30,
85]; confirming that Australian households believe that the medicines could be used for either 1 year or longer after their expiration [
85]. These findings highlighted the need for efforts on public education regarding the rational use of medicines, particularly with respect to medicine expiry date, in order to prevent the problems linked to public health [
86].
Based on the literature, to some extent medicine wastage is inevitable because of several reasons such as patient death, treatment failure, medicine change, and side effects [
7]. Then, in different studies solutions such as producing medicines in smaller packages as well as prescription of medicines for shorter time lags were endorsed as effective approaches [
3,
67,
73,
75,
80,
87,
88]. Ekedahl et al. in their study proposed a feasible way to decrease the volume of unused medicines in which a small “starter pack” is prescribed whenever a new treatment is initiated. Of note, if the consumption stopped, only small volumes would be stocked or discarded [
26]. Additionally, a recent study by Bach et al. reported 27 to 30% wastage in 3.5 mg vials of bortezomib compared to 1.5 mg vials [
88].
The first and most stored medicines were group J (17.4%), among which, Antibiotics are the most known medicines. Despite the fact that in many health systems antibiotics were authorized as prescription-only drugs, they are easily purchased with no prescription [
3,
16,
23,
28,
65,
75]. The gap between the legislation and daily practice, over expectation about antibiotics effectiveness, low awareness regard to antibiotic resistance, adverse event, and high cost of physician consultation have been cited as reasons for antibiotics storage [
89‐
93]. The same evidence has been reported by Sawair et al., indicating that patients visited the second physician because they did not receive any antibiotic from the first physician [
94]. Kelly et al. in their study have cited microbial resistance as a significant public health concern and highlighted that one way of tackling microbial resistance is to limit both the prescription and use of anti-infective medicine for non-bacterial infections especially in societies with lower health literacy level [
85].
Paracetamol (Acetaminophen) belonging to group N, was the most stored medicine by households. This finding is unsurprising, because the paracetamol is the first-line treatment for pain and fever management [
1,
24,
62,
63]. However, the availability, affordability, convenience, marketing, and misconception about its safety compared to NSAIDs (Non-steroidal anti-inflammatory drugs) has made the paracetamol family the first choice of self-medication among people [
1,
24,
62,
63,
65]. Although a few studies reported that keeping a limited stock of these medicines might be cost-saving due to lower physician visit [
3,
28,
65,
66] more studies warned about the rising rate of self-medication as well as medicine wastage and its undesirable consequences [
28,
95‐
97].
According to the results of analysis reported by 6 studies covering 4580 households, medicine storage and wastage were found to be positively associated with households purchasing power; indicating that in households with higher income or in countries whose medicine price is lower, both storage and wastage are more prevalent. This finding has also been confirmed by studies from high-income countries reporting that this problem exists in all over the world and there are factors beyond real health needs that are associated with demand and utilization medicines [
30,
79,
98,
99].
Insurance coverage was recognized as a positive motive for more storage and wastage of medicines among households [
75]. This finding suggested that, although having medical insurance could financially protect household members against catastrophic health expenditures, the lack of strict control on prescription, selling, and demand of medicine could encounter health systems to the increased cost of unnecessary storage and wastage of medicines. Moreover, Sweileh and Zargarzadeh in their study reported a stronger correlation between having medical insurance and medicine storage [
24,
75].
The impact of education on drug storage is interestingly different from that on wastage. Most of the literature reported a positive association between the level of education of the household’s head and the amount of medicine storage [
3,
24,
62,
74,
75]. However, the number of medicine wastage was reported as higher for illiterate or less educated counterparts [
3,
25,
74]. Accordingly, it is obvious that education level could prevent drug wastage through better compliance with the treatment or better storage practice [
3,
23,
28,
62,
74]. Nevertheless, according to the previous studies, educated people more tend to purchase more medicines from retail pharmacies and store medicines for future use, so they are more prone to self-medication [
23,
28,
62,
74].
Some significant differences were found between men and women in terms of medicine storage modality, amount, and wastage. Notably, the higher the rate of in-home storage among women [
23,
64], the lower the wastage rate linked to households who stored medicines and were organized by female subjects [
70]. Other studies have confirmed high storage rates among women [
70,
99,
100] by stating some reasons such as gender-related physiopathology, lifestyle, contact to the health system, and other biological differences like pregnancy [
100,
101]. However, other variations such as women’s tendency to excessive purchase and self-medication, lacks medical reasoning, so they can potentially be considered as the focal point for improvement [
102]. A study by Becker showed that wasted medicine was more frequently used by men compared to women [
87].
Considering our findings, there was a considerable variation in medicine storage place among households in all geographic regions. Since the storage location was reported to be associated with the decreased adherence to treatment, unfavorable clinical outcomes and potentially hazardous consequences [
103‐
105], WHO guideline [
76] seems to be a good solution to solve this problem in which the appropriate place is keeping medicine in an enclosed and cool or dry place, which is inaccessible for children.
The majority of the studies (75%) highlighted that most countries have no guidelines for disposal of medicines, which not only imposes a financial burden on society, but also creates environmental hazards through the accumulation of chemical ingredients in landfills and freshwater resources. In most developed health systems, several schemes have been developed for the disposal of unused medicines that could be adopted as a practical solution by low and middle-income countries. For example, the National Return and Disposal of Unwanted Medicines (Nat RUM) scheme in Australia can be named that provides a route to return leftover medicines to community pharmacies [
77]. Studies conducted in Sweden and Australia suggested a unitary medicine take-over system or educational campaigns at the national level instead of state-run programs [
77,
106]. In Nebraska, especial boxes are placed in pharmacies that allow consumers to return their excessive medicines to the pharmacy [
107]. Arkaravichien et al. [
108] and Yang et al. [
109] in their studies proposed that the national health system can provide financial incentives for pharmacies and households participating in take-back schemes.
Strengths and limitation of the study
This systematic review focused on the most important part of the consumption chain, which is before medicine wastage as well as its related harms to the environment. Furthermore, most of the home storages were reviewed and then reported, so we believe that our study’s results can provide evidence for decision-making at both individual and community levels. Since all the included studies have focused on quantitative analysis of medicine storage, so the household’s preferences or their experiences as one of the key influential factors on establishing inappropriate storage and wastage, has not been addressed decently. Therefore, future research investigating this gap seems to be beneficial.
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