In the United States, approximately eight million people use syringes at home, generating three billion used needles each year.1 Diabetics not only use insulin needles on a regular basis but also use lancets for blood sugar monitoring. Collectively, these objects are called "sharps."
The management of sharps is the responsibility of health care institutions whose health care workers (HCWs) routinely use them. In this setting, there are procedures and policies for the handling and disposal of sharps, but the same is not true in the community. The Philippines currently has no ordinances that regulate the disposal of sharps waste at the community level and poses a threat to public health and safety, and in particular, to garbage disposal workers. Discarded needles may expose waste workers to potential needle stick injuries and infection, since used needles can transmit diseases such as HIV and hepatitis B.2
The objective of phase 1 was to create a validated, self-administered questionnaire to assess the knowledge, attitudes and practices of diabetic patients with regard to the disposal of insulin syringes and needles in the community setting. The objectives of phase 2 were 1) to determine the practices of diabetic patients with regard to their disposal of insulin syringes or needles; 2) to assess their knowledge regarding the correct use of insulin syringes and needles, the hazards of improper disposal, and measures that should be taken to ensure their safe disposal; 3) to assess their attitude towards the safe disposal of sharps; and 4) to identify which factors influence knowledge, attitude and practices towards sharps disposal.
A PubMed search using a combination of the keywords "diabetes," "sharps," "disposal," "needles," and "syringe" yielded eight relevant studies. Six full text articles were retrieved; two had their abstracts available. No local studies were identified except for an unpublished study done by the authors in 2010.3 One study had the actual questionnaire available, while two studies listed the items present in their questionnaire.
The study protocol and informed consent forms were submitted to and approved by the University of the Philippines-Manila Research Ethics Board.
A focus group discussion (FGD) was done to verify if the concepts regarding sharps disposal taken from foreign literature were locally applicable and elucidate those that might be unique to the Filipino setting. Five female and three male patients were recruited from the UP-PGH Diabetes Clinic and separate FGD sessions were conducted for female and male participants.
A conceptual framework was developed to integrate the concepts derived from the review of literature and FGD. This was based on the Health Belief Model (HBM), one of the most widely used theories on health behavior that focus on the beliefs and actions of individuals.4 The HBM as applied to the concepts pertaining to sharps disposal is illustrated in Figure 1.
Click here to download Figure 1Figure 1. Conceptual Framework based on the Health Belief Model
The conceptual framework was used to guide the development of the questionnaire. Socio-demographic factors and clinical factors related to DM were collected. Knowledge pertaining to proper sharps handling and disposal was assessed with 10-item multiple choice items, which also covered other concepts such as disease transmission. The concepts regarding benefits of proper disposal and barriers to this were tackled in nine questions designed to assess attitude. Sources of disposal advice were identified and in addition, patient's own initiative to seek advice was also documented.
The questionnaire items adapted from foreign literature were evaluated in terms of best practice for questionnaire design and for factual correctness. Several questions were rewritten, while others were not adapted if not deemed pertinent. New items were created using data from the literature review, results of the focus group discussion and the authors' unpublished study.3
The output of these processes was a preliminary questionnaire that was critiqued by a medical anthropologist from the clinical epidemiology department. Items that were considered leading were rephrased and suggestions to increase clarity of the items and collect additional data were used to improve the preliminary questionnaire. An endocrinologist reviewed the questionnaire and suggested to revise the knowledge items from a true/false format to multiple choice questions instead. Guides on insulin syringe safety and sharps disposal intended for lay persons were used to support the veracity of the items.5-7
The preliminary questionnaire was submitted to the University of the Philippines (U.P.)-Manila Sentro ng Wikang Pilipino for translation into Filipino.
A total of 130 patients from the UP-PGH Diabetes Clinic participated in the second phase of the study. Inclusion criteria included adult patients (19 years of age or older) who had been using insulin for at least one month. Patients who were illiterate, those with gestational diabetes mellitus and those with difficulty reading the questionnaire due to poor visual acuity were excluded from the study.
For phase 1, a biostatistician was consulted and a sample size of 124 patients was computed for a confidence level of 95%, relative error of 7.5% and non-response rate of 10% with respect to the knowledge of proper sharps disposal, using PASS software.
The data from phase 2 of the study were analyzed by a biostatistician using STATA v12. Multiple logistic regression was done to see which factors were predictive of proper sharps disposal. Linear regression was used to determine which factors influenced the knowledge and attitude scores of the respondents. Item analysis of the multiple-choice questions in the knowledge section was done using PIA v.3, a non-commercial item analysis program used previously to analyze Philippine national-level examinations.
The preliminary questionnaire was pre-tested on 12 patients from the UP-PGH Diabetes Clinic. The respondents took an average of 13 minutes to answer the questionnaire, with a range of 8 to 20 minutes. Majority found the questionnaire easy to understand. A few items were reworded for clarity.
The revised questionnaire was administered to 81 patients. Cronbach's alpha analysis was done for the knowledge and attitudes section and was 0.44 and 0.62 respectively.
A total of 130 diabetic patients participated and fully completed the survey (Table 1). Majority of the respondents were female (65.3%), married (59.7%) and unemployed (71.5%). There were nearly equal numbers of high school and college graduates at 32.6% and 31.8% respectively. Mean duration of diabetes mellitus was 13.6±8.5 years, while mean duration of insulin use was approximately half, at 6.7±6.0 years. Majority (62.7%) had children at their place of residence.
Click here to download Table 1Table 1. Demographic and clinical characteristics of the respondents,N=130
Characteristics pertaining to the use and disposal of insulin syringes are summarized in Table 2. Most of the respondents used insulin stored in vials (62.7%). Majority of sharps were disposed through community garbage collection (82%), either mixed loosely with household waste (13.0%) or placed in a container (76.0%), although 11% practiced both, a sharps container was not used regularly. The most common containers used were plastic bags (38.9%) and plastic bottles (33.6%). Slightly more than a third of the respondents (38.4%) reported pulling or cutting insulin needles prior to disposal.
Click here to download Table 2Table 2. Characteristics related to the use and disposal of insulin syringes and needles*
Out of 129 respondents 32.6% practiced insulin injection outside the home and of these, 66.7% brought their sharps back, while the remainder disposed of them in the nearest trash can. Majority (80.0%) reused their insulin needles or syringes. Only 40.3% reported not having received sharps disposal advice. Doctors were the most common source (48.5%), followed by nurses (21.6%) and family members (13.4%). Only 23.5% indicated that they had previously asked a doctor for advice.
The knowledge of the participants regarding the proper use and disposal of insulin syringes was evaluated using 10 multiple choice questions. Three major concepts were covered: proper syringe/needle use; hazards of improper disposal; and proper syringe/needle disposal practices with two, three and five items respectively. The mean score of the participants was 62.2±15.7%, with fairly similar scores across the three domains (range of 60-66%).
Item analysis was done and the mean item difficulty index (p-value) was 0.623, corresponding to a test of moderate difficulty. This falls within the recommended mean p-value of 0.6-0.8 for a four-option MCQ test.8,9 Item discrimination was computed using the discrimination index (DI) and point-biserial with acceptable values of > 0.2 for both measures.10-12 All the items had acceptable discrimination based on the two measures, with values ranging from 0.22-0.43 and 0.31 to 0.53 respectively, with the exception of one item with a DI of 0.086.
The section of the questionnaire evaluating attitude was comprised of nine items covering five concepts (Table 3). A 5-point Likert scale on agreement was used, ranging from strongly agree (score of 5) to strongly disagree (score of 1). The mean score of the respondents was 3.90±0.58, corresponding to a positive attitude.
Click here to download Table 3Table 3. Distribution of scores per attitude concept
Several factors were analyzed to determine which were predictive of proper sharps disposal (Table 4). Proper disposal was defined as the use of a plastic bottle or metal container to hold the sharps prior to disposal, as recommended by guides from the US EPA and FDA.6,7 Both a longer duration of diabetes and longer duration of insulin use negatively influenced proper disposal with odds ratios of 0.941 and 0.904 respectively.
Click here to download Table 4Table 4. Multiple logistic regression analysis of factors that might influence proper sharps disposal
Factors that influenced the knowledge level of the respondents were also analyzed. Practice of proper disposal, history of needle stick injury to self, college education, male sex and a higher attitude level were associated with a higher knowledge score but none of these reached statistical significance.
Similarly, analysis was done to determine factors predictive of attitude. History of self-inflicted needle stick injury and college education were associated with a more positive attitude towards proper disposal, while the opposite was observed for being married (Table 5).
Click here to download Table 5Table 5. Linear regression analysis of factors that might influence attitude
This study shows that the most common method of disposal for used insulin needles and syringes is through the community disposal system (82%). This finding is similar to that in India and Pakistan where 84.4% and 86% of diabetics use the household garbage bin to dispose of their sharps respectively.13,14
The most common containers used to hold sharps were plastic bags and plastic bottles, the latter are typically soft drink or "mineral water" bottles. These containers are readily available in most Filipino households and patients use them as improvised sharps containers. This habit was also observed in the United Kingdom, where empty beer cans, glass jam jars, envelopes, soap packets, and milk containers were used to hold sharps.15
Nearly one-third of the respondents (32.6%) injected insulin while outside the home. This is comparable to the data of Bouhanick where 26.6% injected insulin while at work.16 Of these patients from European countries, 63% brought their sharps home, whereas 30% threw the sharps in a garbage bin, very near to the corresponding figures of 66.7% and 30.9% observed in the study.
More than half of the respondents (59.7%) reported having received advice regarding sharps disposal, which is slightly lower than the figure of 64.6% reported in the U.K.15 The study noted that 49% received advice from doctors, comparable to the figure of 50% reported by Musselman for U.S. patients.17
Only 23.4% of the respondents said they had previously sought disposal advice from their doctor. This is only slightly higher than the number reported in India at 16.8%.13 Data from Europe reported that only 18.3% of patients inquired from physicians regarding proper disposal, although this figure was reported by physicians and not the patients themselves.16
The mean knowledge score of the participants was 62.2±15.7%, corresponding to a fair or moderate level of knowledge, while the mean attitude score was 3.90±0.58, which represented a positive attitude. Singh and Chapman assessed 303 Indian diabetic patients and classified 65.9%, 23.8% and 10.3% of the participants to have a moderate, high, and low knowledge level respectively. The same authors observed that a low attitude level towards proper sharps disposal was seen in 16.3%, moderate for 67.1% and high for 16.6% of patients.13 Because of the low Cronbach's alpha associated with this section, this datum is not conclusive. Since the low value is likely a result of the limited number of items, additional items to cover the three knowledge domains are suggested. However, since the questionnaire is already fairly long and the respondents often found this section to be the most challenging, an alternative would be to create a questionnaire focused solely on knowledge of sharps use and disposal. This would ameliorate the potential respondent fatigue or loss of interest that occurs when answering long questionnaires.
Majority of the literature reviewed observed that education regarding proper disposal of sharps had a significant and positive impact on patient practices. However, this study noted that the only factors which reached statistical significance were those that exerted a negative influence, particularly a longer duration of diabetes and insulin use.
Several reasons why advice from HCWs did not have a positive impact can be speculated. First, patients might not have followed the advice given. Second, the advice given might not be correct in the first place. Among the 47 patients who reported a physician and/or a nurse to be the source of advice, only 11 were assessed to have a correct disposal method. Third, multiple sources of advice appear to decrease the possibility of correct disposal. Of the 18 patients who reported receiving advice from more than one source aside from a HCW, none were assessed to be consistently practicing a proper disposal method.
It was observed that three patients were able to dispose of their sharps at health care facilities. It is a reasonable assumption that if more health care facilities were to offer this service, patients might be less inclined to dispose their sharps in local trash bins. In particular, this population of respondents all had regular outpatient follow-up and could bring their sharps for disposal on their scheduled visit. However, this did not seem to be the case. When the respondents were asked if they were willing to bring their sharps to the hospital for disposal, only 44.1% of the respondents gave a positive response, 15.7% were uncertain, and 40.2% were not amenable. If the respondents that were uncertain are considered to have a negative response, this would mean nearly two-thirds of the respondents were actually unwilling to bring their sharps to the hospital for disposal. The questionnaire was not designed to determine the reasons for this outcome, therefore it is suggested that these be evaluated further, especially if a hospital-based collection sharps program is planned.
The study has shown that patients of the UP-PGH Diabetes Clinic have a positive attitude and appear to have moderate knowledge towards the correct disposal of insulin syringes and needles. Despite this, only 23.7% were assessed to have acceptable disposal techniques. This implies that adequate attitude and knowledge by itself does not necessarily translate to action. As shown in the Health Belief Model, health-related behavior is influenced by "Cues to Action," which can be regarded as strategies to activate "readiness."18 Therefore, patients might be ready to commit to health-promoting behavior but require an impetus to push them into action, particularly education on proper sharps disposal.
Majority of patients at the UP-PGH DM clinic do not practice acceptable sharps disposal methods. Factors that negatively impact on safe disposal include longer duration of diabetes mellitus and longer duration of insulin use. No factors appeared to influence knowledge significantly. History of previous needle stick injury and college education influenced attitude towards sharps disposal positively, while being married exerted a negative influence.
Patients of the UP-PGH Diabetes Clinic have a positive attitude and apparently moderate knowledge with regard to sharps disposal. Despite this, less than a quarter of patients dispose of their insulin syringes and needles properly. Therefore, it is highly recommended that educational program on sharps disposal in the community setting be initiated.
We would like to thank the following: Merck, Inc., through the Philippine Society of Endocrinology and Metabolism for the research grant awarded to this study, and Mary Ann J. Ladia, Ph.D. of the Department of Clinical Epidemiology, College of Medicine, U.P. Manila for valuable advice in the construction of the questionnaire.
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