Hypothalamic GHRH deficiency is a condition characterized by a clinically significant reduction in the secretion of Growth Hormone-Releasing Hormone by the hypothalamic circuits that orchestrate the activity of pituitary somatotroph cells. GHRH is the primary physiological stimulus for the pulsatile release of growth hormone; when the hypothalamic signal weakens or is interrupted, GH production becomes inadequate and, downstream, the availability of IGF-1, a key mediator of growth effects and numerous metabolic actions, is reduced. The resulting picture may present with statural and weight growth deceleration in childhood or, in adulthood, with a GH deficiency phenotype dominated by alterations in body composition, physical performance and bone health.
Unlike forms of GH deficiency due to primary pituitary damage, GHRH reduction belongs to dysfunctions “upstream” of the hypothalamus pituitary liver and peripheral tissue axis, in which the central problem concerns the quality and rhythmicity of neuroendocrine command. This perspective is relevant because it explains the clinical variability and the possible coexistence with other hypothalamic alterations, and it requires an assessment that considers not only hormone values, but also the pulsatile dynamics of GH, the presence of suppressive factors such as somatostatinergic tone and integration with energy and circadian signals.
Hypothalamic GHRH deficiency, understood as a reduction in hypothalamic drive to GH release with consequent functional deficiency of the axis, is overall uncommon in the general population and often underdiagnosed, especially when the presentation is subtle or when the picture is generically attributed to “GH deficiency” without specific attention to the site of the disorder. In childhood, alterations of the GH IGF-1 axis represent an important treatable cause of short stature, but the precise distribution of hypothalamic forms compared with pituitary forms is difficult to quantify, because in clinical practice the etiopathogenetic distinction requires dynamic and neuroradiological assessments that are not always uniform. In adulthood, GH deficiency is more often secondary to structural hypothalamic pituitary disorders, surgery or cranial irradiation, and the hypothalamic component may be an integral part of regional damage.
An epidemiological chapter closely connected to the concept of GHRH deficiency concerns genetic conditions that interrupt the GHRH GHRH receptor pathway. Although many of these are classically classified as forms of “pituitary” deficiency because of a receptor defect, they represent a human model of failed response to hypothalamic command and clarify how growth can be severely impaired even in the absence of macroscopic lesions. Mutations of the GHRH receptor gene are a recognized cause of autosomal recessive isolated GH deficiency and can cause proportionate dwarfism with reduced GH secretion and low IGF-1 levels. Their epidemiological relevance lies mainly in contexts of consanguinity or in populations with founder effects, where local prevalence may be significantly higher than expected globally.
With regard to risk factors, it is useful to distinguish between conditions that directly reduce GHRH production or release and contexts that alter hypothalamic regulation of the somatotropic system. Organic factors include lesions of the hypothalamic region and third ventricle, such as craniopharyngiomas, gliomas and other suprasellar neoplasms, infiltrative and granulomatous processes, sequelae of central nervous system infections and vascular damage. In these scenarios, deficiency of hypothalamic command may coexist with alterations of other pituitary axes and with disturbances of appetite regulation, body weight and thermoregulation, forming a broader hypothalamic picture.
A clinically highly relevant determinant is exposure to cranial irradiation, especially when it involves the hypothalamic pituitary region. In these cases, GH deficiency may appear after a variable latency and often precedes other hormonal insufficiencies, because the somatotropic axis is particularly vulnerable. Neurosurgical procedures, head trauma and chronic inflammatory diseases of the central nervous system can also predispose to dysfunction of hypothalamic drive, with phenotypes ranging from isolated GH reduction to forms of panhypopituitarism.
Alongside structural causes, there are conditions that suppress GH secretion through central mechanisms without destroying GHRH neurons. Excess weight and insulin resistance, for example, are associated with reduced pulsatile GH secretion and a “functionally low” GH profile that may confuse the diagnosis in dynamic testing. Similarly, chronic systemic diseases, persistent inflammation, liver diseases and kidney diseases can alter the relationship between GH and IGF-1 and modify the hypothalamic signals that regulate the axis. In such contexts, distinguishing primary hypothalamic deficiency from secondary functional suppression becomes essential to avoid inappropriate diagnoses and to guide treatment correctly.
Finally, the physiology of the somatotropic system is closely linked to sleep quality and circadian rhythms. Chronic sleep disorders, night work and circadian misalignment may contribute to a reduction in nocturnal GH peaks, and in predisposed individuals they may accentuate axis vulnerability. This observation reinforces the idea that the epidemiology of GHRH deficiency should not be interpreted only as the rarity of a single entity, but as the result of a complex interaction between hypothalamic anatomical integrity, neuropeptidergic modulation and metabolic and environmental context.
Hypothalamic GHRH deficiency is the outcome of an alteration in the circuits that generate and release the main stimulatory signal for GH secretion. Physiologically, somatotropic hypothalamic output derives from the balance between GHRH and somatostatin, with additional modulation by orexigenic and metabolic signals, including ghrelin and catecholaminergic and serotoninergic systems. The final result is pulsatile GH secretion, with peaks of variable amplitude, particularly pronounced during slow-wave sleep phases. When GHRH is lacking, or when the network that coordinates it becomes disorganized, GH production cannot maintain the patterns needed to support growth, tissue remodeling and metabolic homeostasis.
From an etiological standpoint, the most clearly hypothalamic forms include structural damage to the arcuate and periventricular regions, suprasellar abnormalities and third ventricular lesions that interrupt connectivity between hypothalamic nuclei and the pituitary portal system. In these cases, the pituitary gland may initially be intact but deprived of the correct central command. There are also conditions in which the reduction in somatotropic signaling derives from a relative excess of inhibitory tone, due to increased somatostatin or alterations in neurotransmitters that favor inhibition. This element introduces an important interpretative key: the deficiency is not necessarily the “absence of a hormone”, but the loss of the dynamic balance between stimulus and brake.
A highly useful pathophysiological model is represented by GHRH receptor mutations. In these conditions, GHRH may be present, but the message is not transduced by somatotroph cells, with reduced GH synthesis and secretion and, often, somatotroph hypoplasia. This scenario shows that GHRH signaling is not only an acute trigger for release, but also a trophic factor for somatotroph function. Although the defect is receptor-level and therefore not strictly hypothalamic, it helps explain why a prolonged deficiency of GHRH drive, regardless of cause, may be associated over time with reduced secretory capacity of the pituitary gland.
The pathogenetic core is the reduction of GH peaks and the loss of their temporal organization. Since GH also acts through feedback mechanisms, the decrease in IGF-1 reduces the peripheral brake but is not sufficient to restore a physiological pattern if the hypothalamic generator is compromised. GH also exerts feedback on the somatostatinergic system and on GHRH release, contributing to the shape of secretory bursts. When the hypothalamic component is altered, this regulatory circuit is disrupted and secretion becomes lower and less biologically effective.
The pathophysiological consequences are distributed across several domains. In childhood, reduced GH and IGF-1 translate into decreased growth velocity and delayed skeletal maturation, with an impact on final height if the condition is not recognized in time. Longitudinal growth depends on the proliferation and differentiation of chondrocytes in the growth plate, processes regulated directly and indirectly by the somatotropic axis, and signal deficiency leads to a reduction in the anabolic drive required for epiphyseal plate physiology.
In adulthood, GH deficiency is associated with changes in body composition, typically with increased visceral fat and reduced lean mass, accompanied by reduced exercise capacity, dyslipidemia and alterations in markers of cardiovascular risk. At the skeletal level, reduced remodeling and bone formation may favor a decline in bone mineral density, especially when other pituitary deficiencies coexist or when diagnosis is delayed. From a psychosocial standpoint, reduced energy, deterioration in perceived well-being and vulnerability to mood disorders may emerge, elements that often improve with adequately titrated treatment.
Overall, hypothalamic GHRH deficiency should be interpreted as a disorder of neuroendocrine regulation in which biological information depends on signal dynamics. Quantitative reduction is important, but the loss of pulsatility and circadian synchronization is what most profoundly compromises the physiological effects of GH, making an assessment necessary that brings together regional anatomy, dynamic tests and metabolic context.
The clinical picture of hypothalamic GHRH deficiency varies markedly according to the age at which signal reduction develops and its intensity. This variability reflects the fact that the somatotropic axis is not devoted exclusively to statural growth, but continuously contributes to the control of body composition, lipid and glucose metabolism, bone health and general well-being. Consequently, the dominant signs in childhood do not coincide with those in adults, and the same biological deficiency may translate into different clinical phenotypes.
In childhood, the cardinal sign is a reduction in growth velocity, often accompanied by progressively shorter stature compared with peers and delayed bone age. The history may reveal initially normal growth in the first months of life, followed by slowing during childhood or early school age, when the contribution of GH to linear growth becomes more evident. A somatic appearance with increased relative adiposity, especially truncal, and reduced muscle mass is frequently observed, elements that may be mistakenly interpreted as constitutional if not placed within a coherent auxological picture.
In the most severe and early cases, especially when dysfunction is related to extensive hypothalamic pituitary damage or to genetic forms that drastically reduce the GHRH pathway, short stature may be marked and pubertal maturation may be indirectly influenced, not so much because of a direct effect of GHRH on the gonadotropic axis, but because of the presence of hypothalamic comorbidities or associated hypopituitarism. In these cases, the physical examination must always assess signs of deficiency of other axes, visual field abnormalities, headache, polyuria and polydipsia, and symptoms of hypercortisolism or hypocortisolism if the context suggests them.
In adults, deficiency of the somatotropic system manifests with a set of often non-specific signs. Reduced exercise tolerance, fatigability, decreased strength, increased abdominal fat and worsening of the lipid profile are commonly reported. Reduced bone density, musculoskeletal pain and a tendency toward lower perceived quality of life may occur, with sleep and mood disorders in a proportion of patients. These elements acquire greater clinical value when there is a history of hypothalamic pituitary disease or sequelae of treatments involving the region.
An important aspect is that GH secretion is physiologically reduced in some conditions, including obesity and aging, and therefore compatible symptoms alone are not sufficient to establish a diagnosis. In particular, in patients with overweight or metabolic syndrome, low GH secretion may be a functional phenomenon and not necessarily the expression of a primary hypothalamic deficiency. Consequently, the clinical picture must be interpreted in light of the history, the presence of a regional disorder and the dynamic data of the GH IGF-1 axis.
In both children and adults, the physical examination must include assessment of body composition, growth parameters or weight, blood pressure, signs of dyslipidemia or insulin resistance and any features suggestive of genetic syndromes or hypothalamic lesions. The clinical manifestation, therefore, is not a single sign, but an overall profile that becomes interpretable only through an integrated approach.
Suspicion of hypothalamic GHRH deficiency arises from the convergence of a compatible clinical context and an auxological or metabolic pattern that is not explained by more common causes. In childhood, the element that should activate clinical reasoning is a persistently low growth velocity for age, especially when associated with progressive deviation from percentiles and delayed bone age. The suspicion becomes stronger if low IGF-1 levels are present and if the family history does not support constitutional short stature or simple growth delay. In these cases, consistency between auxological, biochemical and clinical data is more important than a single isolated value.
GHRH deficiency should be considered with particular attention when there is a documented risk of hypothalamic involvement. A history of suprasellar tumors, surgery in the region of the third ventricle, cranial radiotherapy, major head trauma or infiltrative diseases are conditions in which the hypothalamus may be compromised even in the absence of striking neurological signs. In such situations, GH deficiency may be the first endocrine manifestation and may precede other pituitary insufficiencies, making timely suspicion a crucial point in the prevention of complications.
In adults, clinical suspicion should arise especially in the presence of known hypothalamic pituitary disease or a picture of hypopituitarism, because the pre-test probability of GH deficiency increases significantly. Non-specific symptoms such as increased visceral fat, reduced lean mass, dyslipidemia, reduced exercise capacity and deterioration in quality of life acquire diagnostic value when they occur in a context of regional risk and when peripheral markers such as IGF-1 are consistently low for age and sex.
It is equally important to recognize situations that may mimic a deficiency. Obesity reduces the GH response to stimulation tests and may lower GH levels without representing a structural deficiency. Similarly, chronic systemic diseases, persistent inflammatory conditions and liver dysfunctions may reduce IGF-1 and alter the GH IGF-1 relationship. In these contexts, suspicion must be formulated cautiously and accompanied by a comprehensive assessment of clinical status, avoiding attribution to hypothalamic deficiency of what may be explained by functional suppression or peripheral resistance to GH action.
In summary, hypothalamic GHRH deficiency should be suspected when inadequate growth or a phenotype typical of GH deficiency is associated with a risk context for hypothalamic damage or with concordant biochemical elements, and when more likely alternative causes have been reasonably excluded. This step, based on structured clinical reasoning, allows the correct investigations to be initiated and helps avoid both underdiagnosis and unnecessary treatments.
The diagnosis of hypothalamic GHRH deficiency requires a sequential pathway integrating clinical assessment, peripheral indices of the GH IGF-1 axis, dynamic tests and neuroradiology. Since GH is secreted in a pulsatile manner and shows wide intraindividual variability, a random GH measurement has no diagnostic utility. The process must therefore start from solid clinical elements, such as auxological data in children or a hypothalamic pituitary risk context in adults, and continue with investigations aimed at confirming biological deficiency and localizing its origin.
The first level of assessment includes measurement of IGF-1 and, in childhood, also IGFBP-3, interpreted according to age, sex and pubertal stage. Low values may support the suspicion, but they are not sufficient on their own to establish a diagnosis, because IGF-1 is influenced by nutrition, inflammation, liver function, hypothyroidism and glycemic control. For this reason, thyroid status, nutritional assessment and investigation for chronic diseases must be part of the first diagnostic phase, as must an accurate analysis of growth over time and familial genetic targets in children.
Biochemical confirmation of GH deficiency is based on stimulation tests. In childhood, guidelines and consensus documents emphasize that diagnosis is multifactorial and that dynamic tests must be interpreted together with auxological and clinical data, taking into account the limitations of methods and the variability of cut offs. In adults, diagnosis requires provocative testing in the appropriate clinical context, since symptoms and signs are not specific. Available tests include the insulin tolerance test, which remains a reference in many settings, and alternatives used when insulin testing is contraindicated, with consideration of variables that may influence the response, including age, obesity and comorbidities.
To distinguish reduced hypothalamic command from primary pituitary disease, tests assessing the ability of the pituitary gland to respond to stimuli that bypass the hypothalamus may be useful. The use of GHRH in combination with agents that reduce somatostatinergic inhibition, such as arginine or pyridostigmine, has been proposed to enhance the GH response and explore somatotroph integrity. A preserved response in the presence of clinical suspicion may suggest a problem “upstream” of endogenous GHRH release, whereas an absent or markedly reduced response may point toward pituitary somatotroph impairment. However, the use of GHRH in diagnostic testing varies between countries and centers and must be interpreted in the context of local recommendations and the availability of preparations.
Neuroradiology is an essential part of the pathway, because hypothalamic GHRH deficiency often implies a regional problem. Magnetic resonance imaging of the hypothalamic pituitary axis allows identification of suprasellar lesions, pituitary stalk abnormalities, congenital malformations and signs of treatment-related damage. In children, imaging may show abnormalities such as pituitary hypoplasia, ectopic posterior pituitary or stalk defects, elements that support the hypothesis of a central disorder and also guide genetic assessment when appropriate.
When the picture suggests hereditary forms of the somatotropic axis, genetic investigation may contribute to etiological definition. This area includes mutations involving the GHRH GHRH receptor pathway and other genes involved in hypothalamic pituitary development and GH secretion. The diagnosis of hypothalamic GHRH deficiency is therefore the result of a clinical, laboratory and instrumental construction, in which hypothalamic localization must be supported by a coherent context and by evidence excluding more likely alternative causes.
The classification of hypothalamic GHRH deficiency is useful for transforming an endocrinological diagnosis into a treatment and monitoring strategy. The first classificatory axis distinguishes forms related to hypothalamic lesions or dysfunctions from those in which the GHRH pathway is compromised through different mechanisms, including receptor-level conditions that, although not strictly hypothalamic, reproduce a phenotype of failed response to hypothalamic command. This distinction is important because it influences the likelihood of association with other hormonal deficiencies and with non-endocrine hypothalamic symptoms, such as alterations in appetite and thermoregulation.
A second criterion concerns the time of onset. Forms with onset in childhood mainly cause a disorder of linear growth and skeletal maturation, whereas forms with onset in adulthood present as the metabolic and functional syndrome of GH deficiency. In many conditions of hypothalamic pituitary damage, onset is not point-like but progressive, and GH deficiency may appear earlier and more markedly than other insufficiencies. This gradual course requires a classification that takes time and the patient’s trajectory into account.
Severity may be described as a continuum, from a mild reduction in pulsatile secretion to severe deficiency documented by dynamic tests with very low IGF-1 and a coherent clinical picture. In children, severity does not coincide only with the peak value during testing, but with growth velocity, auxological response and the degree of bone age delay. In adults, severity is reflected in the combination of biochemical evidence and clinical impact, bearing in mind that the coexistence of other pituitary deficiencies may amplify the phenotype and that obesity may complicate test interpretation.
It is also useful to distinguish between isolated and associated forms. Isolated deficiency of the somatotropic axis may occur, but in the presence of hypothalamic lesions or regional treatments it is more common to observe associations with ACTH, TSH and gonadotropin deficiencies, or with central diabetes insipidus in pictures involving the posterior pituitary. This classification has practical consequences because it defines the priority for correction of vital axes, the order of hormonal replacement and the safety of initiating GH therapy.
Finally, classification must integrate the dimension of reversibility. Some reductions in hypothalamic drive may improve if the causal factor is removed or if regional inflammation regresses, whereas post-surgical and post-radiation damage is more frequently permanent. From this perspective, diagnosis does not close the pathway but opens it, because defining the type of deficiency also means setting realistic expectations and planning periodic reassessments of the axis.
The main goals of treatment for hypothalamic GHRH deficiency are to restore the biological effects of GH and prevent long-term complications. In clinical practice, the reference therapy is administration of recombinant GH, because it makes it possible to bypass the defect in hypothalamic command and restore tissue exposure to GH in a controllable manner, with increased IGF-1 and improvement of clinical endpoints. The choice of GH, rather than therapies with GHRH or analogues, is related both to greater clinical experience and to regulatory availability and the robustness of evidence across different age groups.
In childhood, GH therapy aims to normalize growth velocity and maximize final height compatibly with the genetic target. Management requires a complete initial assessment, correction of conditions that may reduce the response, such as hypothyroidism or cortisol deficiency, and regular monitoring of growth, bone maturation and IGF-1 levels to avoid undertreatment and overtreatment. Dosage is adapted according to auxological response, pubertal context and tolerability, with attention to clinical signs of GH excess, such as edema, persistent headache and joint pain.
In adults, GH replacement therapy is indicated in the presence of documented deficiency and an appropriate clinical context, with individualized titration based on IGF-1 and clinical parameters. The goal is not to reach a “high” value, but to bring IGF-1 back into an appropriate range for age and improve body composition, lipid profile, bone density and quality of life, while avoiding side effects related to excessive dosing. Prudence is particularly important in patients with metabolic comorbidities and in older subjects, in whom GH sensitivity may vary.
A central element of treatment is management of the underlying causes when present. In the case of hypothalamic lesions, endocrine therapy must be integrated with the neurosurgical or oncological pathway and with neuroradiological surveillance. After cranial radiotherapy, periodic assessment of the pituitary axes is essential, because new deficiencies may appear over time and therapy must be adapted to the patient’s overall endocrine trajectory. In hypopituitarism, cortisol and thyroxine replacement must be optimized before starting GH to reduce risks and improve efficacy.
The use of GHRH analogues has a more limited role. There are specific indications for some analogues in particular contexts, but in GH deficiency due to hypothalamic deficiency, the standard therapy remains recombinant GH. In the rare scenarios in which more physiological pituitary stimulation with GHRH is considered, the approach must be regarded as highly specialized, linked to the availability of the preparations and the possibility of adequate monitoring, and it does not replace the consolidated strategy based on GH.
Alongside hormonal therapy, treatment includes interventions on lifestyle and global health. Structured physical activity, attention to diet, prevention of cardiovascular risk and optimization of bone health are essential components, because GH deficiency influences multiple metabolic pathways and because hormonal therapy alone does not automatically correct all risk determinants. Management of hypothalamic GHRH deficiency is therefore a pathway of integrated endocrine replacement and preventive medicine, with measurable goals and periodic reassessments.
Follow-up of hypothalamic GHRH deficiency must be structured because the condition often occurs within dynamic scenarios, especially when the cause is a regional disease or treatment sequela. In children, monitoring revolves around growth: growth velocity, percentile trajectory, bone maturation and pubertal progression are the key parameters, together with periodic assessment of IGF-1 to verify dose adequacy and reduce the risk of excessive exposure. The visit must include general clinical assessment, blood pressure, body composition and signs of possible side effects, with attention to headache, visual disturbances or symptoms that may suggest intracranial hypertension or progression of regional lesions in predisposed contexts.
In adults, follow-up is aimed at optimizing clinical benefit and ensuring safety. GH titration is guided by IGF-1, but it must always be correlated with clinical response, changes in body composition, lipid and glycemic profile and tolerability. Edema, arthralgias, paresthesias and worsening glycemic control may indicate the need for dose reduction, especially in patients with insulin resistance. Assessment of quality of life and physical performance is an integral part of monitoring, because it represents one of the main goals of replacement therapy in adults.
An essential chapter of follow-up concerns skeletal health. In patients with long-standing GH deficiency, especially if associated with hypogonadism or other pituitary deficiencies, the risk of reduced bone density is higher. Bone densitometry, fracture risk assessment and optimization of vitamin D and calcium should be considered according to age, sex and individual risk factors, remembering that the effect of GH on bone requires time and that the benefit is greater when treatment is integrated with correction of the other axes.
When GHRH deficiency is related to hypothalamic lesions or oncological treatments, follow-up must include neuroradiological surveillance according to specialist indication and periodic reassessment of the entire pituitary status. New deficiencies may emerge over time, and changes in body weight, replacement therapy or general clinical condition may modify GH requirements. Multidisciplinary management, with an endocrinologist, neurosurgeon, oncologist and radiologist when necessary, is often decisive for maintaining coherence and safety over the long term.
Finally, in cases in which a functional or modifiable component is suspected, follow-up must include correction of factors that may suppress the axis, such as excess weight, sleep alterations and chronic comorbidities. In these scenarios, reassessment of the picture after lifestyle interventions may help distinguish between persistent deficiency and secondary suppression, avoiding unnecessary therapies or allowing more appropriate titration. Monitoring, therefore, is not a repetitive act but an adaptive process that follows the evolution of the patient.
The prognosis of hypothalamic GHRH deficiency depends mainly on early diagnosis, the underlying cause and the quality of replacement treatment. In childhood, timely recognition and adequately monitored GH therapy allow recovery of growth velocity in many cases and significantly improve height outcome. The potential for recovery is greater when the deficiency is identified before growth delay becomes marked and when chronic diseases or complex hypothalamic pituitary damage that limit response do not coexist.
In adults, life expectancy is not generally impaired by GH deficiency alone, but the condition is associated with a less favorable cardiovascular and metabolic risk profile, especially in the presence of hypopituitarism and other endocrine deficiencies. Well-titrated replacement therapy can improve body composition, lipids, bone density and perceived well-being, but it requires a balance between efficacy and safety and continuous attention to comorbidities such as diabetes and hypertension.
The main complications of untreated or inadequately treated deficiency derive from the loss of the anabolic and regulatory effects of GH. In children, the most evident complication is short stature with possible psychological and social impact, accompanied by alterations in body composition and, in more complex pictures, maturational delays related to the hypothalamic pituitary context. Bone age delay may be present and, if therapy is started late, the window for recovery of final height may narrow.
In adults, chronic GH deficiency is associated with increased visceral fat, reduced lean mass, dyslipidemia and reduced exercise capacity. These alterations may contribute to worsening cardiometabolic risk, especially when other endocrine deficiencies coexist or when the patient has pre-existing risk factors. At the skeletal level, reduced remodeling may predispose to decreased mineral density and, over time, to a higher risk of skeletal fragility, particularly if hypogonadism is not adequately treated.
Another domain of complications concerns quality of life. Tiredness, reduced energy, worsening psychological well-being and a perceived reduction in physical performance are frequently reported elements and may improve with replacement therapy, although the magnitude of benefit varies among individuals. Functional prognosis is therefore closely linked to the ability to personalize treatment and monitor clinically relevant outcomes, without limiting follow-up to the IGF-1 value alone.
In pictures due to hypothalamic disease, prognosis is conditioned above all by the evolution of the underlying lesion and its multisystem consequences. In these patients, endocrine complications represent part of the overall problem and must be integrated into a care pathway that includes oncological or neurological surveillance, management of other pituitary axes and interventions on nutrition and lifestyle. In summary, when GHRH deficiency is correctly identified and treated with a specialist approach, the outcome is often favorable, but it requires continuity of care and surveillance targeted to the most relevant long-term complications.