Introduction

Accounting for 85% of all stroke-related deaths worldwide, acute stroke is a significant public health problem, especially for countries undergoing epidemiological transition¹, In Mexico, stroke is the seventh leading cause of death, with over 19,000 deaths in 2021². Stroke is also a leading cause of disability in adults and the second most common cause of dementia. Given its impact on the economically active population and quality of life, improving stroke prevention and treatment must be of high priority for public health-care systems worldwide.

Acute stroke can present with multiple signs and symptoms, usually affecting one side of the body and potentially associated with decreased alertness³. Sometimes, its initial presentation is subtle and may not be recognized by bystanders. There has been substantial effort to strengthen the recognition of stroke among health-care personnel and the general population⁴; however, specific studies regarding its impact in Mexico have yet to be conducted⁵.

Stroke prevention is more cost-efficient than treatment. This is done through modifiable risk factors control, such as a healthy diet, physical activity, and pharmacological treatment⁶. Acute reperfusion treatments (intravenous thrombolysis or mechanical thrombectomy) have improved functional outcomes; however, these therapies can only be applied in certain scenarios and within a specific timeframe. In Mexico, 66% of stroke patients arrive at a hospital after 6 h of symptom onset, reducing the chances of successful reperfusion therapy¹. In a recent Mexican study, 17.4% of patients arrived < 4.5 h, and only 7.6% received intravenous thrombolysis⁷.

Stroke knowledge varies worldwide and even within countries⁸, with up to 70% recognition of at least one symptom and one risk factor. Among the Mexican population, information regarding public knowledge of acute stroke treatments is lacking⁹. Increased stroke knowledge could lead to earlier recognition of stroke and potentially increase the proportion of patients arriving in time for reperfusion therapy. Our study provides updated information about stroke knowledge in the general population.

Materials and methods

For this study, we designed a questionnaire addressing stroke knowledge, including its definition and associated concepts, risk factors, symptoms, and treatments. This questionnaire was divided into six different sections: (1) knowledge of different terms used by non-healthcare professionals to name "stroke;" (2) definition of common terms associated with stroke; (3) recognition of the main clinical manifestations of stroke; (4) recognition of risk factors for stroke; (5) knowledge of acute treatment of stroke; and (6) perceived stroke mortality.

The first section consisted of applicants answering all the terms they knew in Spanish that were equivalent to stroke, which is very variable among native Spanish speakers. In the second, we asked the participants to define in their own words different terms related to "stroke" ("brain infarction," "brain hemorrhage," "subarachnoid hemorrhage," "cerebral venous thrombosis," "transient ischemic attack," and "aneurysm"). In the third, we asked the participants to answer all the symptoms they knew of stroke openly, and we compared the answers to a pre-established list; if they did not name any of these pre-established symptoms, we prompted the responses, and we requested them to answer "yes" or "no." In the fourth part, we provided a list of risk factors for stroke, including four correct risk factors (hypertension, diabetes, dyslipidemia, and obesity) and six wrong answers (sexually transmitted disease [STD], pregnancy, hepatitis, asthma, cataract, gastritis), to which participants answered "yes" or "no" if they considered it to be associated with increased stroke risk. Finally, we investigated whether they recognized stroke as a treatable disease, the correct treatments they knew about, and whether they were aware of intravenous thrombolysis and mechanical thrombectomy. In the condominium-complex group, the questionnaire included the following questions: "Do you know how much time we have to administer the thrombolytic therapy after the first symptom?" and "Out of 100 patients suffering from stroke, how many do you think will die?" These questions were not asked in the pharmaceutical company survey to reduce bias because these data are included in sales strategies. The complete survey is provided as supplementary material.

We trained 4^th-year medical students in the systemized application of the survey, who then applied the survey to willing participants aged 18 years and older, under supervision from the authors. The survey was applied in two locations in Mexico City: A middle-class condominium complex (Villa Olímpica – a condominium complex in the south of Mexico City and close to the National Autonomous University of Mexico – inhabited by several researchers from this University), and the headquarters of a pharmaceutical company (producers of Alteplase).

The permit was submitted to the authorities of each site to survey inhabitants and workers. We had permission accepted in 2016 by the condominium and in 2018 by the pharmaceutical company. Each site was surveyed over 2 days, the first (condominium complex) in December 2016 and the second (pharmaceutical company) in August 2018. We do not consider that the conduction of the survey in two different years poses a risk for different degrees of knowledge, given that no promotion or educational program for stroke existed or was promoted in those years in Mexico City. The questionnaire was applied to all volunteer inhabitants at the condominium in a door-to-door search, and in the pharmaceutical company, we only applied it to non-medical administrative personnel, which included employees of the sales, accounting, and marketing departments.

The permit was submitted to the authorities of each site to survey inhabitants and workers. We had permission accepted in 2016 by the condominium and in 2018 by the pharmaceutical company. Each site was surveyed over 2 days, the first (condominium complex) in December 2016 and the second (pharmaceutical company) in August 2018. We devised a composite score, ranging from 0 to 12 points, to summarize and compare results between groups. Surveys with missing data were excluded from the study.

Results

In total, we surveyed 535 people, excluding 36 surveys due to being incomplete. Table 1 summarizes results from 499 participants, with 277 in the condominium complex group (median age 58 years [IQR 43-70]; 55% female; mean years of education 16.7 [SD 4.40]) and 222 in the company’s building (median age 33 [IQR 27-42] years; 54.9% male; mean years of education 15.3 [SD 2.28]). Age was higher in the condominium complex group, and the educational level was significantly lower among the company group.

Regarding stroke concepts, half of the participants correctly defined stroke and cerebral infarction. Brain hemorrhage was the most correctly defined concept in 68.7%, but subarachnoid hemorrhage and transient ischemic attack were the lowest (8% and 9.6%, respectively). Brain aneurysm, a concept commonly associated with stroke in Spanish laypeople language, was correctly defined only in 18.4%.

The recognition of initial stroke symptoms was good overall, with 71% recognizing at least one sign and 53.7% recognizing two or more. Perhaps, the downside point is that a third part of the participants could not identify any symptoms. The complete Cincinnati triad was only mentioned by 13.2%, possibly due to our country’s need for a specific stroke education program. True risk factors were extensively recognized in all participants, and false risk factors were rarely recognized, besides pregnancy and STD which were referred to as risk factors by approximately a fifth of participants.

Stroke treatment knowledge was higher in the company than in the condos, which is expected since they produce Alteplase. Despite this, 75.8% of participants could not mention a single treatment for stroke. When applying the composite score, there was no statistically significant difference between the groups’ overall stroke knowledge.

Figure 1 describes the recognized proportion of surveyed risk factors. Hypertension was the most recognized risk factor, with 95%, while dyslipidemia was the least known risk factor with 60%. Although no false risk factor was recognized more than any true ones, unrelated diseases such as cataracts can be identified as such when suggested.

Figure 1 True (blue) and false (red) risk factors recognized by participants in %. 

In the extended version of the questionnaire for the condominium group (n = 277), we obtained the following responses. Regarding the window time to administer thrombolytics, we obtained 48 responses (17.3%), of which 36 (75%) considered a window to apply thrombolytics < 3 h, 1 (2.08%) between 3 and 4.5 h, and 11 (22.9%) > 4.5 h. Furthermore, in this group, the average perceived mortality from stroke was 39.7% (0-100) with 122 participants (44%) reporting < 30% mortality, 93 (33.5%) between 30 and 60%, and the remaining 62 (22.3) > 60%.

We found no correlation between age and composite score (p = 0.92), with a weak correlation (0.230) between education level and composite score (p < 0.001).

Discussion

This study found that stroke knowledge in these selected Mexican populations remains heterogeneous, ranging from a greater understanding of risk factor recognition to a deficient knowledge of stroke definitions and treatments. It is worthwhile to compare the overall results with those obtained by Góngora-Rivera et al. in 2003, also obtained in a median-income population in Mexico City⁹. Knowledge of at least one stroke symptom was higher in our study (33% vs. 60%). The proportion of risk factor recognition was also higher in our study; however, the differences in methodology could explain this finding (prompted answers vs. open questions). The use of distractors (false risk factors) was only used in our study, demonstrating a low recognition of these compared to the actual risk factors, and indicating a low level of misinformation in this area.

The lack of universal terminology in Spanish for stroke makes it difficult to establish public information programs to recognize acute stroke signs and symptoms accurately. This factor may contribute to the poor knowledge among our population¹⁰. Most of our population uses different terms to name a stroke. However, as demonstrated in our questionnaire, they lack a deeper understanding of these diverse concepts. This language barrier problem represents a challenge for developing stroke education programs in Spanish-speaking countries¹¹. This may not be exclusive to the Spanish-speaking population, as this remains understudied. As an example, some of the interviewed population refer to hemorrhage as "derrame" ("blood spillover"). They may also consider it a synonym of "aneurysm," and both terms are at least as commonly used by the general population. It is essential to recognize this lingual disparity when comparing the knowledge of stroke between diverse language-speaking people, and critical for creating and promoting adequate education programs, which cannot be the same for all.

The recognition of presenting stroke symptoms was far greater than in earlier studies in our city⁹. For example, the percentage of people able to recognize one alarm symptom was almost double. The proportion of recognition of initial symptoms was also high compared to similar studies in other Latin American countries. In Colombia, an open-ended questionnaire demonstrated that 65% could not name an initial stroke symptom, and 54% could not name a risk factor¹². In Brazil, 22% could not mention any presenting symptom, closer to the proportion found in our study¹³ Given differences in methodology, these comparisons must be interpreted with caution; however, they could be explained by greater years of education in our selected population. Paralysis on one side of the body and mouth deviation is the most recognized symptoms; moreover, other important presenting symptoms such as coma or acute visual disturbances were less in this study.

One crucial point in our study, which has not been previously searched for in our country and is only seldom investigated in other survey-based studies, is the knowledge of thrombolytic and interventional therapies for stroke and the existence of a window time. It has been previously demonstrated that knowledge of these points is low among the general population¹⁴. Another important fact is that understanding risk factors and stroke presentation may not be associated with a higher proportion of patients arriving in window time, as found in an interview study in Brazil¹⁵. This has also been observed even among the more exposed to stroke population of health-care professionals. This could mean that there is not enough divulgation of these problems among the general population, but it could also represent the more complex nature of these terms. Directing efforts toward increasing knowledge in these areas may be helpful¹⁶. In a study done in patients hospitalized for acute stroke, the factors associated with arrival within the window time for IVT were recognition of the first symptom as part of the stroke, the use of an ambulance, and the knowledge of the existence of a thrombolytic therapy¹⁷,¹⁸.

The variation in survey years could introduce bias, as the prominence of mechanical thrombectomy may have increased during that period. Despite the absence of any promoted educational programs for stroke treatment in Mexico City during those years, we cannot guarantee that company personnel remained uninformed on this matter, and we recognize this as a limitation in this study.

Conclusion

Knowledge of stroke, in general, is determined by years of education and the language-specific terms for stroke at the general population level. Despite the greater general knowledge with increasing years of schooling, the knowledge of thrombolytic therapies and time windows for reperfusion therapies was low even among our educated population. We hope that our data could be helpful in the development of public education programs, aiming at creating information directed in lay language (but unified) terms, and about the importance of very early hospital arrival in functional outcomes and prognosis.